CN110426337B - Rock-soil body osmotic deformation testing device under low stress condition and testing method thereof - Google Patents
Rock-soil body osmotic deformation testing device under low stress condition and testing method thereof Download PDFInfo
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- CN110426337B CN110426337B CN201910814353.8A CN201910814353A CN110426337B CN 110426337 B CN110426337 B CN 110426337B CN 201910814353 A CN201910814353 A CN 201910814353A CN 110426337 B CN110426337 B CN 110426337B
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- 239000002689 soil Substances 0.000 title claims abstract description 163
- 238000012360 testing method Methods 0.000 title claims abstract description 80
- 230000003204 osmotic effect Effects 0.000 title claims abstract description 42
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 182
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 99
- 239000010959 steel Substances 0.000 claims abstract description 99
- 239000004575 stone Substances 0.000 claims abstract description 55
- 238000001035 drying Methods 0.000 claims abstract description 41
- 230000008595 infiltration Effects 0.000 claims abstract description 16
- 238000001764 infiltration Methods 0.000 claims abstract description 16
- 238000000034 method Methods 0.000 claims abstract description 15
- 230000035699 permeability Effects 0.000 claims description 22
- 239000012528 membrane Substances 0.000 claims description 15
- 230000009471 action Effects 0.000 claims description 14
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 12
- 238000005259 measurement Methods 0.000 claims description 12
- 238000003860 storage Methods 0.000 claims description 8
- 239000011435 rock Substances 0.000 claims description 7
- 235000012255 calcium oxide Nutrition 0.000 claims description 6
- 239000000292 calcium oxide Substances 0.000 claims description 6
- 239000003292 glue Substances 0.000 claims description 5
- 230000008569 process Effects 0.000 claims description 5
- 238000010998 test method Methods 0.000 claims description 5
- 238000012544 monitoring process Methods 0.000 claims description 4
- 230000000149 penetrating effect Effects 0.000 claims description 4
- 230000001680 brushing effect Effects 0.000 claims description 3
- 230000008859 change Effects 0.000 claims description 3
- 238000013461 design Methods 0.000 claims description 3
- 238000007599 discharging Methods 0.000 claims description 3
- 238000005553 drilling Methods 0.000 claims description 3
- 238000005498 polishing Methods 0.000 claims description 3
- 238000009738 saturating Methods 0.000 claims description 3
- 230000006641 stabilisation Effects 0.000 claims 2
- 238000011105 stabilization Methods 0.000 claims 2
- 230000035515 penetration Effects 0.000 claims 1
- 230000007613 environmental effect Effects 0.000 abstract description 3
- 238000011065 in-situ storage Methods 0.000 description 9
- 238000010586 diagram Methods 0.000 description 4
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 238000012669 compression test Methods 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 3
- 238000005303 weighing Methods 0.000 description 3
- 230000005484 gravity Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000002274 desiccant Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000001932 seasonal effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B5/00—Measuring arrangements characterised by the use of mechanical techniques
- G01B5/30—Measuring arrangements characterised by the use of mechanical techniques for measuring the deformation in a solid, e.g. mechanical strain gauge
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
- G01N15/0806—Details, e.g. sample holders, mounting samples for testing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
- G01N15/082—Investigating permeability by forcing a fluid through a sample
- G01N15/0826—Investigating permeability by forcing a fluid through a sample and measuring fluid flow rate, i.e. permeation rate or pressure change
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- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Dispersion Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Fluid Mechanics (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
Abstract
The invention discloses a rock-soil body osmotic deformation testing device under a low-stress condition and a testing method thereof, comprising an osmotic system; the water supply system is connected with a water inlet of the permeation system, an axial pressure output end of the vertical load loading system is connected with an axial pressure loading end of the permeation system for axial pressure loading, a confining pressure output end of the circumferential load loading system is connected with a confining pressure loading end of the permeation system for confining pressure loading, a hot gas output end of the dry-wet circulation system is connected with a hot gas inlet of the permeation system, a water outlet of the permeation system is connected with a seepage flow measuring system, a hot gas outlet of the permeation system is connected with a hot gas drying end of the dry-wet circulation system for dry-wet circulation test, and an input end of the deformation measuring system is connected with an axial deformation end and a circumferential deformation end of the permeation system; the infiltration system comprises a base, upper and lower water permeable stones, a round water impermeable steel plate and a round water permeable steel plate. The method solves the problem that the low stress and the environmental conditions of the dry and wet circulation are not considered at present to influence the authenticity of the experimental result.
Description
Technical Field
The invention belongs to the field of geotechnical engineering tests, and relates to a device and a method for testing the osmotic deformation of a rock-soil body under a low-stress condition.
Background
The osmotic deformation characteristics of the rock-soil mass are one of the hot spots of concern for geotechnical engineering. In recent years, shallow instability of a side slope under the seasonal rainfall effect is frequent, and the main reason is that moisture migrates and permeates in a side slope rock-soil body to generate complex physical, chemical and mechanical comprehensive reaction, so that the rock-soil body structure is damaged, the strength is reduced, the shallow instability is caused, and huge economic loss is caused. Therefore, the research on the permeation deformation characteristics of the rock-soil body under the condition of low stress and dry-wet cycle is of great significance.
At present, the permeability characteristics of the rock-soil body are studied mainly by adopting a constant water head permeameter device and a variable water head permeameter device, and the two devices can test the permeability coefficient of the rock-soil body, but the conditions are too ideal, the environment conditions of low stress and dry-wet circulation are not considered, the actual condition of the rock-soil body can not be simulated, the influence on the authenticity of a test result is large, and the test result is not accurate enough. In general, the rock-soil body is difficult to consider the combined action of comprehensive factors such as low stress and dry-wet circulation at the same time in the test, and only one factor of the low stress or the dry-wet circulation is considered for action, so that the test error is larger.
There are many methods for testing the circumferential deformation of a rock-soil body, for example: the circumferential deformation of the rock-soil body can be measured by sticking a strain gauge on the surface of the rock-soil body, but the local deformation of the rock-soil body is difficult to reflect the integral deformation condition of the rock-soil body due to the fact that the rock-soil body has non-uniformity, and the measurement accuracy is not high. Meanwhile, the requirements on test conditions are high, an advanced triaxial compression test instrument is needed, the operation is complex, and the cost is high. In addition, an axial pressure loading pump is often adopted to load axial pressure at present, an operation system is complex, the applied pressure is large, the lower axial pressure is inconvenient to apply, and the axial pressure loading pump is not suitable for a rock-soil body permeation deformation test under a low-stress condition.
Disclosure of Invention
The invention aims to provide a rock-soil body osmotic deformation testing device under a low-stress condition, so as to solve the problem that the reality of an experimental result is affected by the existing rock-soil body osmotic deformation testing device without considering the environmental conditions of low stress and dry-wet circulation, the problem that the measurement accuracy is low due to the fact that a strain gauge is locally stuck on the surface of a rock-soil body to measure the circumferential deformation of the rock-soil body, and the problems that an axial pressure loading pump is high in pressure, low in axial pressure and complex in operation system are inconvenient to load at present, and the problems that the existing loading system is high in requirement on the experimental conditions, and the existing loading system is complex in operation and high in cost are solved.
The invention further aims to provide a test method of the rock-soil body osmotic deformation test device under the condition of low stress, so as to solve the problem that the test error is large due to the fact that the existing test method does not consider the combined action of comprehensive factors such as low stress, dry-wet circulation and the like.
The technical scheme adopted by the invention is that the rock-soil body osmotic deformation testing device under the condition of low stress comprises an osmotic system, a water supply system, a vertical load loading system, a circumferential load loading system, a dry-wet circulating system, a seepage flow measuring system and a deformation measuring system; the water supply system is connected with a water inlet of the permeation system, an axial pressure output end of the vertical load loading system is connected with an axial pressure loading end of the permeation system, a confining pressure output end of the circumferential load loading system is connected with a confining pressure loading end of the permeation system, a hot gas output end of the dry-wet circulation system is connected with a hot gas inlet of the permeation system, a water outlet of the permeation system is connected with a seepage flow measuring system, a hot gas outlet of the permeation system is connected with a hot gas drying end of the dry-wet circulation system, and an input end of the deformation measuring system is connected with an axial deformation end and a circumferential deformation end of the permeation system.
Further, the infiltration system consists of a base, a lower permeable stone, an upper permeable stone, a round impermeable steel plate, a cylindrical rock-soil body sample and a round permeable steel plate; the cylindrical rock-soil body sample is located on the base, the lower permeable stone is arranged between the cylindrical rock-soil body sample and the base, and the top of the cylindrical rock-soil body sample is provided with the upper permeable stone, the round permeable steel plate and the round impermeable steel plate which are sequentially arranged from bottom to top.
Further, a ball support and two circular through holes are arranged on the circular watertight steel plate, and a hollow hemispherical groove is arranged on the ball support; the infiltration system is connected with the water supply system through one circular through hole on the circular watertight steel plate, is connected with the dry-wet circulation system through the other circular through hole on the circular watertight steel plate, and is connected with the vertical load loading system through a ball support on the circular watertight steel plate;
the base is provided with a drainage groove, a water outlet hole and a plurality of circles of annular grooves which are nested in sequence from outside to inside; the water outlet hole is embedded in the annular groove of the innermost ring, one end of the drainage groove is communicated with the annular groove of the outermost ring, and the other end of the drainage groove is communicated with the water outlet hole after being communicated with all the annular grooves inwards in sequence; the lower permeable stone is attached to the annular groove on the base, and the diameter of the lower permeable stone is equal to that of the annular groove on the outermost ring of the base; the infiltration system is respectively connected with the seepage flow measuring system and the dry-wet circulating system through water outlets on the base.
Further, the vertical load loading system consists of a resistance weight, an inclined rod, a vertical loading rod, a loading weight tray and a loading weight; the vertical rod is vertically fixed on one side of the infiltration system, one end of the inclined rod is rotationally connected with the upper part of the vertical rod by a bolt, and the loading weight tray is fixed on the other end of the inclined rod; the vertical loading rod is positioned between the vertical rod and the loading weight tray; one end of the vertical loading rod is rotationally connected with the inclined rod through a bolt, a steel ball matched with the hollow hemispherical groove of the ball support is arranged at the other end of the vertical loading rod, and the vertical loading system is meshed and fixed with the ball support of the penetrating system through the steel ball on the vertical loading rod and the hollow hemispherical groove on the ball support; the drag weight is fixed in the one end of diagonal bar and vertical pole fixed connection, and the drag weight is located vertical pole and keeps away from the one side of vertical loading pole, places the loading weight in the loading weight tray.
Further, the circumferential load loading system is a plurality of layers of elastic rubber films which are sequentially sleeved on the outer side surface of the cylindrical rock-soil body sample, and the elastic rubber film of the first layer is fixedly sleeved on the outer side surface of the cylindrical rock-soil body sample through waterproof glue;
the lower permeable stone, the upper permeable stone, the round impermeable steel plate and the round permeable steel plate are all positioned in the elastic rubber film of the first layer; the diameters of the lower permeable stone, the upper permeable stone, the round impermeable steel plate, the cylindrical rock-soil body sample and the round permeable steel plate are equal to the inner diameter of the elastic rubber membrane, and the outer side walls of the lower permeable stone, the upper permeable stone, the round impermeable steel plate, the cylindrical rock-soil body sample and the round permeable steel plate are contacted with the inner wall of the elastic rubber membrane of the first layer.
Further, the water supply system consists of a water storage device, a water inlet pipe and a water suction pump; one end of the water inlet pipe is communicated with the water storage device through the water suction pump, the other end of the water inlet pipe is communicated with a circular through hole on a circular watertight steel plate of the permeation system, and the water inlet pipe is provided with a first valve and a manometer;
the deformation measuring system consists of an axial deformation measuring system and a circumferential deformation measuring system;
the axial deformation measuring system consists of a fixed rod and a dial indicator, wherein the dial indicator is vertically fixed on the fixed rod, and a measuring head of the dial indicator is arranged on the circular watertight steel plate and is contacted with the circular watertight steel plate;
The circumferential deformation measuring system consists of a range finder, a supporting rod and a rotatable base; the rotatable base is sleeved on the outer side wall of the lower part of the base and can rotate around the base; the support rod is positioned on the side surface of the permeation system and is vertically fixed on the rotatable base; the distance measuring instrument is horizontally fixed on the supporting rod, and the distance measuring end of the distance measuring instrument faces to the cylindrical rock-soil body sample;
the output end of the range finder is electrically connected with the computer.
Further, the dry-wet circulating system consists of an air heater, a vacuum pump and a drying device; the air heater is communicated with the water inlet pipe through a second valve, the vacuum pump is communicated with the other circular through hole on the circular watertight steel plate of the infiltration system through an air pipe, and the drying device is communicated with the water outlet hole on the base of the infiltration system through a water outlet pipe.
Further, the seepage flow measuring system consists of a water collector and an electronic balance, wherein the water collector is arranged on the electronic balance;
one end of the water outlet pipe is connected with the water outlet hole of the base, the other end of the water outlet pipe is divided into two branches, one branch is communicated with the drying device through a third valve, and the other branch is communicated with the water collector of the seepage flow measuring system through a fifth valve;
one end of the air pipe is communicated with a circular through hole in the circular watertight steel plate, the other end of the air pipe is divided into two branches, one branch is connected with the vacuum pump through a fourth valve, and the other branch is communicated with the outside air through a sixth valve;
The vertical rod, the fixed rod and the rotatable base are all arranged on a test bed, and the test bed is divided into a first layer of table top and a second layer of table top; the vertical rod, the fixed rod and the rotatable base are fixed on the first layer of table top, and the drying device and the electronic balance are placed on the second layer of table top; the water outlet pipe penetrates through the first layer of table top and then is divided into two branches which are respectively communicated with the drying device and the water collector in a one-to-one correspondence manner;
the rotatable base is a bearing, the inner ring of the rotatable base is fixedly connected with the test bed, and the outer ring of the rotatable base is fixedly connected with the support rod; the base is embedded in the inner ring of the rotatable base and is fixedly connected with the test bed;
the supporting rod consists of a vertical rod, a cross rod and an adjusting rod, and the range finder is fixed on the adjusting rod; one end of the vertical rod is fixedly connected with the outer ring of the rotatable base, the other end of the vertical rod is fixedly connected with a horizontal rod which is horizontally arranged, a vertical threaded through hole is formed in the horizontal rod, an external thread matched with the threaded through hole is formed in the adjusting rod, and the adjusting rod is in threaded connection with the horizontal rod through the external thread on the adjusting rod and the threaded through hole on the horizontal rod;
the thickness of the lower permeable stone and the upper permeable stone is 10mm;
the distance meter adopts a laser distance meter;
the thickness of the elastic rubber film is 0.5-1 mm.
S1, preparing a cylindrical rock-soil body sample, and carrying out core drilling, polishing and demoulding on raw rock to prepare the cylindrical rock-soil body sample required by a test;
s2, assembling a deformation amount testing system, namely brushing a layer of waterproof glue on the outer side wall of a cylindrical rock-soil body sample, sleeving a first layer of elastic rubber film, placing an upper permeable stone, a round permeable steel plate and a round impermeable steel plate on the upper surface of the cylindrical rock-soil body sample, placing a lower permeable stone on the lower surface of the cylindrical rock-soil body sample, wrapping the lower permeable stone with the first layer of elastic rubber film, attaching the upper permeable stone to the round permeable steel plate, and attaching the round permeable steel plate to the round impermeable steel plate;
s3, confining pressure loading, namely sequentially sleeving a plurality of layers of elastic rubber films on the outer side of the elastic rubber film of the first layer so as to meet the requirement of applying designed confining pressure;
s4, loading vertical load, namely, occluding and fixing a steel ball at the lower end of a vertical loading rod and a ball support on a round waterproof steel plate through a hollow hemispherical groove of the steel ball, and then placing a loading weight with a loading design weight into a loading weight tray;
s5, performing permeation control, namely opening a first valve to enable water to flow through a water inlet pipe, sequentially flowing through a water pump, a pressure meter and a round water-impermeable steel plate, and controlling water pressure and water flow required by permeation through the pressure meter and the first valve;
S6, dry and wet circulation control, namely firstly opening a first valve and a sixth valve to enable water flow to enter the lower portion of a circular watertight steel plate, closing the first valve and the sixth valve when water flows out of an air pipe branch where the sixth valve is located, closing the fifth valve when the weight of water in a water collector is unchanged, then opening a fourth valve and a vacuum pump to discharge air in a cylindrical rock-soil body sample, saturating the cylindrical rock-soil body sample, closing the fourth valve and the vacuum pump after 24 hours, opening a second valve, a third valve and a hot air blower to enable hot air to pass through the cylindrical rock-soil body sample to take away water, entering a drying device to dehumidify, closing the second valve and the hot air blower until the cylindrical rock-soil body sample is dried, then opening the sixth valve to enable the dehumidified hot air to be discharged from the air pipe after passing through a water outlet pipe and the cylindrical rock-soil body sample, and the dry and wet circulation is realized; repeating the step until the number of dry and wet circulation times required by the test is reached;
s7, deformation measurement and permeability coefficient monitoring, namely monitoring vertical deformation and annular integral deformation through real-time reading of a dial indicator and a range finder, weighing a water collector and a drying device by an electronic balance every t time periods, recording the mass of the water collector and the drying device, and obtaining the permeability coefficient through calculating the water quantity passing through a water outlet pipe and the water quantity passing through the drying device in unit time; and according to the axial pressure and confining pressure loaded on the cylindrical rock-soil body sample, the vertical deformation and the annular integral deformation thereof, the change rule of the osmotic coefficient under the action of different osmotic pressures under the dry-wet circulation condition is obtained.
Further, the permeability coefficient of the cylindrical rock-soil body sample in the t time period is determined according to the following formula:
wherein d is the diameter of the cylindrical rock-soil body sample, Q is the seepage flow through the cylindrical rock-soil body sample after the osmotic pressure is loaded stably, H is the height of the cylindrical rock-soil body sample, and P is the osmotic pressure, namely the water pressure;
and after the osmotic pressure is loaded stably, determining the seepage flow Q of the cylindrical rock-soil body sample according to the following formula:
Q＝(m 1 -m′ 1 )+(m 2 -m′ 2 )；
wherein m 'is' 1 For the initial weight of the water collector, m' 2 For the initial weight of the drying apparatus, m 1 For the weight of the water collector after being stabilized in the loading t time period, m 2 The weight of the drying device after being stabilized in the loading t time period is given;
and when the moisture content of the drying device is increased to 70% of the mass of the quicklime, the cylindrical rock-soil body sample is considered to be dried, and the second valve and the air heater are closed.
The beneficial effects of the invention are as follows:
(1) The experimental device can simulate the rock-soil body in-situ three-way low-stress state and the dry-wet circulation condition when the shallow layer of the side slope is unstable, so that the influence of the disturbance of the rock-soil body on the experimental result is reduced. The device solves the problem that the reality of experimental results is affected because the existing rock-soil body osmotic deformation testing device does not consider the environmental conditions of low stress and dry-wet circulation.
(2) The experimental device can test the permeability coefficient, the axial deformation and the circumferential deformation of the rock-soil body under the combined action of the three-dimensional low stress state and the dry-wet circulation in-situ, and can further calculate the evolution rule of the permeability coefficient, the axial deformation and the circumferential deformation of the rock-soil body under the combined action of the three-dimensional low stress state and the dry-wet circulation in-situ, and the obtained rock-soil body permeability deformation parameter is basically consistent with the permeability deformation parameter obtained by the side slope shallow rock-soil body in-situ test, so that the measurement error is small. The method solves the problems that the existing test method is difficult to consider the combined action of low stress, dry and wet circulation and other comprehensive factors at the same time, and the influence of the combined action on the rock and soil mass is not considered, so that the test error is large.
(3) By utilizing the lever principle, the lever is transformed to form a shaft pressure loading system, the weight disc is regulated to load the weight, the shaft pressure loaded on the rock-soil body sample is precisely controlled, the operation is convenient and labor-saving, and the problems that the shaft pressure loading pump is used for applying high pressure, the loading of lower shaft pressure is inconvenient and the operation system is complex are solved.
(4) The laser emission head of the laser range finder is driven by the rotatable base to wind the rock-soil body for a circle, and the laser emission head moves up and down through the adjusting rod, so that the compression quantity, namely the circumferential deformation quantity, of each point of the cylindrical rock-soil body sample is measured, and meanwhile, the vertical deformation quantity can be measured through the reading of the dial indicator, the display is visual, the operation is simple, and the integral deformation of the rock-soil body can be accurately measured. The device solves the problem that the measurement accuracy is low because the existing rock-soil body osmotic deformation testing device locally sticks strain gauges on the surface of the rock-soil body to measure the circumferential deformation.
(5) The experimental device has the advantages of integrated functions of various systems, simple structure and convenient operation, does not need to be provided with an advanced triaxial compression test instrument, has lower cost, and solves the problems that the conventional rock-soil body osmotic deformation testing device has high requirements on test conditions, needs to be provided with the advanced triaxial compression test instrument, and is complex to operate and high in cost. Meanwhile, the combined action of low stress, dry and wet circulation and other comprehensive factors is considered, so that the practicability is high.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic structural diagram of a rock-soil body osmotic deformation testing device under the condition of low stress.
FIG. 2 is a schematic view of the base of the rock-soil body osmotic deformation testing device under the condition of low stress of the invention.
FIG. 3 is a schematic view of a circular water permeable steel plate of the rock-soil body osmotic deformation testing device under the low stress condition of the invention.
FIG. 4 is a schematic diagram of the circumferential deformation testing system of the rock-soil body osmotic deformation testing device under the low-stress condition.
Fig. 5 is a schematic view of vertical load loading of the rock-soil body osmotic deformation testing device under the low stress condition of the invention.
FIG. 6 is a graph of the relationship between permeability coefficient of a rock-soil body and confining pressure under low stress conditions of the present invention.
FIG. 7 is a graph of the relationship between vertical deformation of the rock-soil body and confining pressure under the low stress condition of the invention.
FIG. 8 is a graph of the relationship between the hoop deformation of a rock-soil body and the confining pressure under the low stress condition of the invention.
FIG. 9 is a graph of the relationship between permeability coefficient of a rock-soil body and axial pressure under low stress conditions of the present invention.
Fig. 10 is a graph of vertical deformation of a rock-soil body versus axial compression under low stress conditions of the present invention.
FIG. 11 is a graph of the relationship between the hoop deformation of the rock and soil mass and the axial compression under low stress conditions of the present invention.
In the figure, 1, a test bench, 11, a first layer of table top, 12, a second layer of table top, 2, a penetrating system, 21, a base, 22, a lower permeable stone, 23, an elastic rubber membrane, 24, an upper permeable stone, 25, a round impermeable steel plate, 26, a cylindrical rock-soil body sample, 27, a round permeable steel plate, 28, a water outlet pipe, 29, a drainage groove, 3, a water supply system, 31, a water storage device, 32, a manometer, 33, a water inlet pipe, 34, a water suction pump, 4, a vertical load loading system, 41, a resistance weight, 42, an inclined rod, 43, a vertical rod, 44, a vertical loading rod, 45, a loading weight tray, 46, a loading weight, 51, a hot air blower, 52, a vacuum pump, and 53, and a drying device. 61. Dial indicator 62, distance meter 63, support rod 64, rotatable base 65, water collector 66 and electronic balance.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention provides a rock-soil body osmotic deformation testing device under a low-stress condition, which is shown in figure 1 and comprises an osmotic system 2, a water supply system 3, a vertical load loading system 4, a circumferential load loading system, a dry-wet circulating system, an osmotic flow measuring system and a deformation measuring system. The water supply system 3 is connected with a water inlet of the permeation system 2, an axial pressure output end of the vertical load loading system 4 is connected with an axial pressure loading end of the permeation system 2, a confining pressure output end of the annular load loading system is connected with a confining pressure loading end of the permeation system 2, a hot gas output end of the dry-wet circulation system is connected with a hot gas inlet of the permeation system 2, a water outlet of the permeation system 2 is connected with a seepage flow measuring system, a hot gas outlet of the permeation system 2 is connected with a hot gas drying end of the dry-wet circulation system, and an input end of the deformation measuring system is connected with an axial deformation end and an annular deformation end of the permeation device 2.
The infiltration system 2 is composed of a base 21, a lower permeable stone 22, an upper permeable stone 24, a circular impermeable steel plate 25, a cylindrical rock-soil body sample 26, and a circular permeable steel plate 27. The cylindrical rock-soil body sample 26 is located on the base 21, the lower permeable stone 22 is placed between the cylindrical rock-soil body sample 26 and the base 21, and the top of the cylindrical rock-soil body sample 26 is provided with the upper permeable stone 24, the circular permeable steel plate 27 and the circular impermeable steel plate 25 which are placed in sequence from bottom to top. The circular watertight steel plate 25 is provided with a ball support and two circular through holes. The infiltration system 2 is connected with the water supply system 3 through one circular through hole on the circular watertight steel plate 25, is connected with the dry-wet circulation system through the other circular through hole on the circular watertight steel plate 25, and is connected with the vertical load loading system 4 through a ball support on the circular watertight steel plate 25. As shown in fig. 2, the base 21 is provided with a drainage groove 29, a water outlet hole and a plurality of circles of annular grooves which are nested in sequence from outside to inside, the water outlet hole is used for being connected with a seepage flow measuring system, the water outlet hole is embedded in the annular groove of the innermost circle, one end of the drainage groove 29 is communicated with the annular groove of the outermost circle, the other end of the drainage groove is communicated with the water outlet hole after being communicated with all annular grooves in the annular groove of the outermost circle in sequence, the lower permeable stone 22 is attached to the annular groove on the base 21, and the diameter of the lower permeable stone 22 is consistent with that of the annular groove of the outermost circle on the base 21. As shown in fig. 3, the circular water permeable steel plate 27 is a steel plate uniformly provided with water permeable holes.
The water supply system 3 consists of a water storage device 31, a water inlet pipe 33 and a water suction pump 34. One end of the water inlet pipe 33 is communicated with the water storage device 31 through the water suction pump 34, the other end of the water inlet pipe is communicated with a circular through hole on the circular waterproof steel plate 25 of the permeation system 2, and the water inlet pipe 33 is provided with a first valve (valve K1) and a pressure gauge 32. The water storage device 31 is a vessel such as a water tank or a water bucket which can hold water.
The vertical load loading system 4 consists of a drag weight 41, an inclined bar 42, a vertical bar 43, a vertical loading bar 44, a loading weight tray 45 and a loading weight 46. The vertical rod 43 is vertically fixed on one side of the infiltration system 2, one end of the diagonal rod 42 is rotatably connected with the upper part of the vertical rod 43 by a bolt (i.e. the diagonal rod 42 can rotate left and right in a vertical plane around the connection point of the diagonal rod 42 and the vertical rod 43 by the bolt), and the loading weight tray 45 is fixed on the other end of the diagonal rod 42. The vertical loading bar 44 is located between the vertical bar 43 and the loading weight tray 45. One end of the vertical loading rod 44 is rotatably connected with the diagonal rod 42 by a bolt (i.e. the vertical loading rod 44 can rotate left and right in a vertical plane around the connection point of the vertical loading rod and the diagonal rod 42 by the bolt), and the other end of the vertical loading rod is provided with a steel ball which is meshed and fixed with a ball support on the circular watertight steel plate 25 of the infiltration system 2, wherein the ball support is a hollow hemispherical groove. The vertical load loading system 4 can be separated from the circular watertight steel plate 25 by arranging the steel balls and the ball supports. The drag weight 41 is fixed at one end of the diagonal rod 42 fixedly connected with the vertical rod 43, and the drag weight 41 is positioned at one side of the vertical rod 43 away from the vertical loading rod 44, and the loading weight 46 is placed in the loading weight tray 45.
The circumferential load loading system is a multi-layer elastic rubber film 23 (the material is the same as that of the rubber ring) sequentially sleeved on the outer side surface of the cylindrical rock-soil body sample 26, and the confining pressure born by the soil sample is controlled by sleeved rubber molds with different layers. The elastic rubber film 23 has a thickness of 0.5 to 1mm and an inner diameter corresponding to the diameter of the rock-soil body sample. The lower permeable stone 22, the upper permeable stone 24, the circular impermeable steel plate 25 and the circular permeable steel plate 27 are all positioned in the elastic rubber membrane 23 of the first layer, the diameters of the lower permeable stone 22, the upper permeable stone 24, the circular impermeable steel plate 25, the cylindrical rock-soil body sample 26 and the circular permeable steel plate 27 are all equal to the inner diameter of the elastic rubber membrane 23, and the outer side wall of the lower permeable stone is in contact with the elastic rubber membrane 23 of the first layer.
The relationship between the deformation amount of the elastic rubber film 23 and the elastic force thereof, namely the confining pressure, is as follows:
σ 3 ＝10600ε；
the confining pressure is calculated as follows:
in the above, sigma 3 Represents confining pressure, namely elasticity of the elastic rubber film 23, epsilon is elasticity modulus of the elastic rubber film 23, b is thickness of the elastic rubber film 23, d 0 Is elastic rubberThe diameter of the membrane 23, n, is the number of layers of the elastomeric rubber membrane 23.
The dry-wet circulation system is composed of an air heater 51, a vacuum pump 52 and a drying device 53. The air heater 51 is communicated with the water inlet pipe 33 through a second valve (valve K2), the vacuum pump 52 is communicated with another circular through hole on the circular water impermeable steel plate of the permeation system 2 through an air pipe, and the drying device 53 is communicated with a water outlet hole on the base 21 of the permeation system 2 through the water outlet pipe 28. The drying device 53 in this embodiment is a vessel (glass bottle or the like) containing a drying agent such as quicklime, and the quicklime is selected, so that the drying device is easy to obtain and economical. One end of the air pipe is communicated with a circular through hole on a circular waterproof steel plate 25 of the permeation system 2, the other end of the air pipe is divided into two branches, one branch is connected with the vacuum pump 52 through a fourth valve (valve K4), and the other branch is communicated with the outside air through a sixth valve (valve K6).
The deformation measuring system is composed of an axial deformation measuring system and a circumferential deformation measuring system, the axial deformation measuring system of the embodiment is composed of a fixed rod and a dial indicator 61, the dial indicator 61 is vertically fixed on the fixed rod, and a measuring head of the dial indicator is arranged on the circular watertight steel plate 25 and is contacted with the circular watertight steel plate 25. The hoop deflection measuring system is composed of a distance meter 62, a supporting rod 63 and a rotatable base 64, wherein the distance meter 62 adopts a laser distance meter in the embodiment. The rotatable base 64 is sleeved on the outer side wall of the base 21 of the permeation system 2 and can rotate around the base 21; the laser rangefinder is fixed in the bracing piece 63 on the level, and bracing piece 63 is fixed in on rotatable base 64 vertically, and bracing piece 63 is located infiltration system 2 side, and the laser emission head of laser rangefinder is towards the lateral wall of cylindrical ground body sample 26. The invention can also adopt other rangefinders, adopts a laser rangefinder, has higher precision and is convenient to operate.
Each time the overall circumferential deformation of the cylindrical rock-soil body sample 26 is measured, the laser emission head of the laser range finder is driven by the rotatable base 64 to wind the cylindrical rock-soil body sample 26 for a circle, and moves up and down through the adjusting rod, so that the circumferential deformation of each point of the cylindrical rock-soil body sample 26 is measured, the range finder 62 is connected with a computer, the measured data are collected into the computer, then a scatter diagram is drawn on the measured circumferential deformation data of each point of the cylindrical rock-soil body sample 26, and linear fitting and variance analysis are carried out to obtain the overall circumferential deformation of the cylindrical rock-soil body sample 26.
The seepage flow measuring system consists of a water collector 65 and an electronic balance 66, one end of a water outlet pipe 28 is connected with the seepage system 2, the other end is divided into two branches, one branch is communicated with a drying device 53 of the dry-wet circulating system through a third valve (valve K3), and the other branch is communicated with the water collector 65 of the seepage flow measuring system through a fifth valve (valve K5). The water flows into the water collector 65 through the water outlet pipe 28 and the fifth valve, the water collector 65 is placed on the electronic balance 66, and the electronic balance 66 is used for weighing the water collector 65 to obtain seepage.
The vertical rod 43 of the vertical load loading system 4 and the rotatable base 64 of the deformation amount measuring system are both placed on the test stand 1, and the test stand 1 is divided into a first layer of table top 11 and a second layer of table top 12. The vertical rod 43 of the vertical load loading system 4 is fixed on the first layer table top 11, the rotatable base 64 of the deformation measuring system is placed on the first layer table top 11, the drying device 53 and the electronic balance 66 are placed on the second layer table top 12, and the water outlet pipe 28 penetrates through the first layer table top and then is divided into two branches, and is respectively communicated with the drying device 53 and the water collector 65. The test stand 1 is made of a material having a certain bearing capacity, such as steel or concrete. The dimensional parameters of the cylindrical rock-soil body sample 26 are obtained by enlarging or reducing the size of the ring-knife seepage test sample.
The rotatable base 64 is a bearing, the inner ring of which is fixedly connected with the test stand 1, the outer ring of which is fixedly connected with the support rod 63, and the base 21 of the infiltration system 2 is embedded in the inner ring of the rotatable base 64, and the base 21 is fixedly connected with the test stand 1. The supporting rod 63 is composed of a vertical rod, a cross rod and an adjusting rod, and the range finder 62 is fixed on the adjusting rod. One end of the vertical rod is fixedly connected with the outer ring of the rotatable base 64, the other end of the vertical rod is fixedly connected with a horizontally placed cross rod, a vertical threaded through hole is formed in the cross rod, an external thread matched with the threaded through hole is arranged on the adjusting rod, and the adjusting rod is in threaded connection with the cross rod through the external thread on the adjusting rod and the threaded through hole on the cross rod. The rotatable base 64 drives the distance meter 62 to rotate around the cylindrical rock-soil body sample 26 for one circle, and the height of the distance meter 62 is adjusted through threaded connection of the adjusting rod and the cross rod so as to measure the integral circumferential deformation of the cylindrical rock-soil body sample 26.
The thickness of the lower and upper permeable stones 22, 24 was 10mm and the diameter was 100mm.
The rock-soil body osmotic deformation testing method under the low-stress condition comprises the following specific steps:
s1, preparing a cylindrical rock-soil body sample 26, and preparing the cylindrical rock-soil body sample 26 required by a test by performing procedures such as drilling, coring, polishing, demoulding and the like on raw rock;
Step S2, assembling a seepage deformation testing device, brushing a layer of waterproof glue on the outer side wall of a cylindrical rock-soil body sample 26, sleeving an elastic rubber membrane 23, placing an upper permeable stone 24, a round permeable steel plate 27 and a round impermeable steel plate 25 on the upper surface of the cylindrical rock-soil body sample 26, placing a lower permeable stone 22 on the lower surface of the cylindrical rock-soil body sample 26, wrapping the lower permeable stone 22 by the elastic rubber membrane 23, attaching the upper permeable stone 24 to the round permeable steel plate 27, and attaching the round permeable steel plate 27 to the round impermeable steel plate 25.
And S3, confining pressure loading, namely sequentially sleeving n layers (n=2, 3 and 4 … …) of elastic rubber films on the outer side of the elastic rubber film 23 of the first layer so as to meet the requirement of applying the designed confining pressure.
And S4, loading vertical load, namely, occluding and fixing the lower end of the vertical loading rod 44 with a ball support on the circular watertight steel plate 25, and then placing the loading weight 46 for loading the design weight into the loading weight tray 45.
Step S5, permeation control, namely opening a first valve, enabling water to flow into the water suction pump 34, the pressure measuring meter 32 and the circular watertight steel plate 25 in sequence through the water inlet pipe 33, penetrating the cylindrical rock-soil body sample 26, and controlling the pressure required by permeation through the pressure measuring meter 32 and the first valve.
Step S6, dry and wet circulation control, namely firstly opening a first valve and a sixth valve to enable water flow to enter the lower part of a circular water-impermeable steel plate 25, closing the first valve and the sixth valve when water flow overflows from an air pipe branch where the sixth valve is located, closing the fifth valve and a vacuum pump 52 when water flow completely flows into a water collector 65 (namely when the weight of water in the water collector 65 is unchanged), discharging air in a rock-soil body and water, saturating a cylindrical rock-soil body sample 26, closing the fourth valve and the vacuum pump 52 after 24 hours, opening a second valve, a third valve and a hot air blower 51 to enable hot air to pass through the cylindrical rock-soil body sample 26, then entering a drying device 53 to dehumidify, weighing and recording by an electronic balance 66 every hour, closing the second valve and the hot air blower 51 when the water content is increased to 70% of the mass of quicklime (namely, the rock-soil body sample is considered to be dried when the water content is increased to 70% of the hot air of the mass of quicklime), and then opening the sixth valve to enable the cylindrical rock-soil body sample to be dehumidified, and discharging the cylindrical rock-soil body sample from the air pipe 26 after the water outlet pipe 28 and 26 to circulate the dry sample; this step was repeated until the number of wet and dry cycles required for the test was reached.
In step S7, the deformation measurement and the permeability coefficient monitoring are performed, the real-time readings of the dial indicator 61 and the range finder 62 are used to monitor the vertical deformation and the circumferential deformation respectively, the electronic balance 66 is used to weigh the water collector 65 and the drying device 53 at intervals, the mass of the water collector 65 and the drying device 53 is recorded, and the permeability coefficient is obtained by calculating the water quantity passing through the water outlet pipe 28 and the water quantity passing through the drying device 53 in unit time.
As shown in fig. 5, a vertical load loading schematic diagram is shown, where F1 is the gravity of the drag weight 41, F2 is the axial loading force applied by the vertical loading rod 44, F3 is the gravity of the loading weight 46, l1 is the moment arm acted by F1, l2 is the moment arm acted by F2, l3 is the moment arm acted by F3, and the moment balance of the rod can be obtained according to the following steps:
F1·l1＝F2·l2+F3·l3；
therefore, on the premise that the mass of the resistance weight 41 is known, the horizontal distance from the resistance weight 41 to the vertical rod 43, the horizontal distance from the vertical loading rod 44 to the vertical rod 43 and the horizontal distance from the loading weight tray 45 to the vertical rod 43, the mass of the loading weight 46 can be calculated according to the above formula according to the axle pressure (the axial loading force required by the vertical loading rod 44) required to be loaded, and then the loading weight 46 with the corresponding mass is loaded in the loading weight tray 45, so that one axial loading is completed.
The weight m of the water collector 65 is weighed with an electronic balance at intervals t 1 And the weight m of the drying device 53 2 Let the weight of the water collector 65 be m 'at the beginning' 1 The weight of the drying device 53 is m' 2 Thereby obtaining the seepage rate of the rock and soil mass sample within the t time period as Q= (m) 1 -m′ 1 )+(m 2 -m′ 2 ) Further under osmotic pressure (water pressure) P, the permeability coefficient of the cylindrical rock-soil body sample 26 over the period t may be determined according to the following equation:
where d is the diameter of the cylindrical rock-soil body sample 26, Q is the seepage flow through the cylindrical rock-soil body sample 26 after the osmotic pressure is stable, and H is the height of the cylindrical rock-soil body sample 26, where the formula can study the change rule of the rock-soil body osmotic coefficient under the action of different axial pressures or confining pressures under the condition of dry-wet circulation.
Let us assume the axial pressure sigma 1 It is certain that different confining pressures sigma are applied to the cylindrical rock-soil body sample 26 by applying different layers of elastic rubber films 23 3 The circumferential deformation L occurring under different shaft pressure and confining pressure ratios can be measured by the readings of the dial gauge 61 and the range finder 62 3 And vertical deformation L 4 Analyzing the data according to the circumferential deformation L 3 And vertical deformation L 4 From different confining pressures sigma 3 The relationship of the axle pressure and the surrounding pressure ratio can be established as follows:
Let-down pressure sigma 3 It is certain that different vertical loads are applied to the cylindrical rock-soil body sample 26 by the vertical load loading system 4The vertical deformation L under different shaft pressure and confining pressure ratios can be measured by the readings of the dial gauge 61 and the range finder 62 1 And the amount of circumferential deformation L 2 Analyzing the data according to the vertical deformation L 1 And the amount of circumferential deformation L 2 From different axial pressure sigma 1 The relationship of the axle pressure and the surrounding pressure ratio can be established as follows:
by controlling and loading different axial pressures and confining pressures, the osmotic deformation condition of the rock-soil body under the condition of low stress can be obtained.
And analyzing the test data to obtain a rock-soil body osmotic deformation parameter which is basically consistent with an osmotic deformation parameter obtained by in-situ testing of the rock-soil body on the shallow layer of the side slope. As shown in fig. 6, is the in-axis pressure sigma 1 At a certain time, the graph of the relation between the permeability coefficient and the confining pressure of the cylindrical rock-soil body sample obtained by the rock-soil body permeability deformation testing device under the low-stress condition is basically consistent with the result obtained by rock-soil body in-situ test measurement, and the effectiveness and the accuracy of the device are illustrated. As shown in fig. 7 to 8, it can be seen that the axial pressure σ is 1 At a certain time, the vertical deformation of the cylindrical rock-soil body sample obtained by the rock-soil body osmotic deformation test device under the low-stress condition and the relation between the circumferential deformation and the confining pressure are basically consistent with the results obtained by rock-soil in-situ test measurement, so that the effectiveness and the accuracy of the device are demonstrated.
As shown in FIG. 9, is at ambient pressure σ 3 At a certain time, the graph of the relation between the permeability coefficient and the axial pressure of the cylindrical rock-soil body sample obtained by the test of the rock-soil body permeability deformation testing device under the low-stress condition shows that the graph is basically consistent with the result obtained by the rock-soil body in-situ test measurement, thereby illustrating the effectiveness of the deviceSex and accuracy. As shown in fig. 10 to 11, it can be seen that at the confining pressure σ 3 At a certain time, the vertical deformation and the relationship between the circumferential deformation and the axial pressure of the cylindrical rock-soil body sample obtained by the rock-soil body osmotic deformation test device under the low-stress condition are basically consistent with the measurement result of rock-soil in-situ test measurement, so that the effectiveness and the accuracy of the device are demonstrated.
It is noted that in the present invention, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.
Claims (8)
1. The rock-soil body seepage deformation testing device under the low-stress condition is characterized by comprising a seepage system (2), a water supply system (3), a vertical load loading system (4), a circumferential load loading system, a dry-wet circulating system, a seepage flow measuring system and a deformation measuring system;
the water supply system (3) is connected with a water inlet of the permeation system (2), an axial pressure output end of the vertical load loading system (4) is connected with an axial pressure loading end of the permeation system (2), a confining pressure output end of the circumferential load loading system is connected with a confining pressure loading end of the permeation system (2), a hot gas output end of the dry-wet circulation system is connected with a hot gas inlet of the permeation system (2), a water outlet of the permeation system (2) is connected with a seepage flow measuring system, a hot gas outlet of the permeation system (2) is connected with a hot gas drying end of the dry-wet circulation system, and an input end of the deformation measuring system is connected with an axial deformation end and a circumferential deformation end of the permeation system (2);
The infiltration system (2) consists of a base (21), a lower permeable stone (22), an upper permeable stone (24), a circular impermeable steel plate (25), a cylindrical rock-soil body sample (26) and a circular permeable steel plate (27); the cylindrical rock-soil body sample (26) is positioned on the base (21), the lower permeable stone (22) is arranged between the cylindrical rock-soil body sample (26) and the base (21), and the top of the cylindrical rock-soil body sample (26) is provided with an upper permeable stone (24), a circular permeable steel plate (27) and a circular impermeable steel plate (25) which are sequentially arranged from bottom to top;
the round waterproof steel plate (25) is provided with a ball support and two round through holes, and the ball support is provided with a hollow hemispherical groove; the infiltration system (2) is connected with the water supply system (3) through one circular through hole on the circular water-impermeable steel plate (25), is connected with the dry-wet circulation system through the other circular through hole on the circular water-impermeable steel plate (25), and is connected with the vertical load loading system (4) through a ball support on the circular water-impermeable steel plate (25);
the annular load loading system is formed by sequentially sleeving a plurality of layers of elastic rubber films (23) with the same specification on the outer side surface of a cylindrical rock-soil body sample (26), and the elastic rubber film (23) of the first layer is fixedly sleeved on the outer side surface of the cylindrical rock-soil body sample (26) through waterproof glue;
The lower permeable stone (22), the upper permeable stone (24), the round impermeable steel plate (25) and the round permeable steel plate (27) are all positioned in the elastic rubber membrane (23) of the first layer; the diameters of the lower permeable stone (22), the upper permeable stone (24), the circular impermeable steel plate (25), the cylindrical rock-soil body sample (26) and the circular permeable steel plate (27) are equal to the inner diameter of the elastic rubber membrane (23), and the outer side walls of the lower permeable stone (22), the upper permeable stone (24), the circular impermeable steel plate and the circular permeable steel plate are in contact with the inner wall of the elastic rubber membrane (23) of the first layer.
2. The rock-soil body permeation deformation testing device under the low-stress condition according to claim 1, wherein the base (21) is provided with a drainage groove (29), a water outlet hole and a plurality of circles of annular grooves which are nested in sequence from outside to inside; the water outlet hole is embedded in the annular groove of the innermost ring, one end of the drainage groove (29) is communicated with the annular groove of the outermost ring, and the other end of the drainage groove is communicated with the water outlet hole after being communicated with all the annular grooves inwards in sequence; the lower permeable stone (22) is attached to the annular groove on the base (21), and the diameter of the lower permeable stone (22) is equal to that of the annular groove on the outermost ring of the base (21); the infiltration system (2) is respectively connected with the seepage flow measuring system and the dry-wet circulating system through water outlets on the base (21);
The thickness of the elastic rubber film (23) is 0.5-1 mm.
3. A rock and soil body osmotic deformation test device under a low stress condition according to claim 1, characterized in that the vertical load loading system (4) consists of a resistance weight (41), an inclined rod (42), a vertical rod (43), a vertical loading rod (44), a loading weight tray (45) and a loading weight (46); the vertical rod (43) is vertically fixed on one side of the permeation system (2), one end of the inclined rod (42) is rotationally connected with the upper part of the vertical rod (43) through a bolt, and the loading weight tray (45) is fixed on the other end of the inclined rod (42); the vertical loading rod (44) is positioned between the vertical rod (43) and the loading weight tray (45); one end of the vertical loading rod (44) is rotationally connected with the diagonal rod (42) through a bolt, a steel ball matched with the hollow hemispherical groove of the ball support is arranged at the other end of the vertical loading rod, and the vertical loading system (4) is meshed and fixed with the ball support of the penetrating system (2) through the steel ball on the vertical loading rod (44) and the hollow hemispherical groove on the ball support; the drag weight (41) is fixed at one end of the inclined rod (42) fixedly connected with the vertical rod (43), the drag weight (41) is positioned at one side of the vertical rod (43) far away from the vertical loading rod (44), and the loading weight (46) is placed in the loading weight tray (45).
4. A rock-soil body penetration deformation testing device under a low stress condition according to any one of claims 1-3, wherein the water supply system (3) consists of a water storage device (31), a water inlet pipe (33) and a water suction pump (34); one end of a water inlet pipe (33) is communicated with a water storage device (31) through a water suction pump (34), the other end of the water inlet pipe is communicated with a circular through hole on a circular water impermeable steel plate (25) of the permeation system (2), and a first valve and a pressure meter (32) are arranged on the water inlet pipe (33);
the deformation measuring system consists of an axial deformation measuring system and a circumferential deformation measuring system;
the axial deformation measuring system consists of a fixed rod and a dial indicator (61), wherein the dial indicator (61) is vertically fixed on the fixed rod, and a measuring head of the dial indicator is arranged on the circular water-impermeable steel plate (25) and is contacted with the circular water-impermeable steel plate (25);
the circumferential deformation measuring system consists of a distance meter (62), a supporting rod (63) and a rotatable base (64); the rotatable base (64) is sleeved on the outer side wall of the lower part of the base (21) and can rotate around the base (21); the supporting rod (63) is positioned on the side surface of the permeation system (2) and is vertically fixed on the rotatable base (64); the distance measuring instrument (62) is horizontally fixed on the supporting rod (63), and the distance measuring end of the distance measuring instrument faces to the cylindrical rock-soil body sample (26);
An output of the distance meter (62) is electrically connected to the computer.
5. The rock-soil body permeation deformation testing device under the low stress condition according to claim 4, wherein the dry-wet circulation system consists of a hot air blower (51), a vacuum pump (52) and a drying device (53); the air heater (51) is communicated with the water inlet pipe (33) through a second valve, the vacuum pump (52) is communicated with another circular through hole on the circular water impermeable steel plate (25) of the permeation system (2) through an air pipe, and the drying device (53) is communicated with a water outlet hole on the base (21) of the permeation system (2) through a water outlet pipe (28).
6. The rock-soil body seepage deformation testing device under the low stress condition according to claim 5, wherein the seepage flow measuring system consists of a water collector (65) and an electronic balance (66), and the water collector (65) is arranged on the electronic balance (66);
one end of the water outlet pipe (28) is connected with a water outlet hole of the base (21), the other end of the water outlet pipe is divided into two branches, one branch is communicated with the drying device (53) through a third valve, and the other branch is communicated with a water collector (65) of the seepage flow measuring system through a fifth valve;
one end of the air pipe is communicated with a circular through hole on the circular water-impermeable steel plate (25), the other end of the air pipe is divided into two branches, one branch is connected with the vacuum pump (52) through a fourth valve, and the other branch is communicated with the outside air through a sixth valve;
The vertical rod (43), the fixed rod and the rotatable base (64) are all arranged on the test bed (1), and the test bed (1) is divided into a first layer of table top (11) and a second layer of table top (12); the vertical rod (43), the fixed rod and the rotatable base (64) are fixed on the first layer table top (11), and the drying device (53) and the electronic balance (66) are placed on the second layer table top (12); the water outlet pipe (28) penetrates through the first layer of table top and then is divided into two branches which are respectively communicated with the drying device (53) and the water collector (65) in a one-to-one correspondence manner;
the rotatable base (64) is a bearing, the inner ring of the rotatable base is fixedly connected with the test bed (1), and the outer ring of the rotatable base is fixedly connected with the supporting rod (63); the base (21) is embedded in the inner ring of the rotatable base (64) and is fixedly connected with the test bed (1);
the supporting rod (63) consists of a vertical rod, a cross rod and an adjusting rod, and the range finder (62) is fixed on the adjusting rod; one end of the vertical rod is fixedly connected with the outer ring of the rotatable base (64), the other end of the vertical rod is fixedly connected with a horizontally placed cross rod, a vertical threaded through hole is formed in the cross rod, external threads matched with the threaded through hole are formed in the adjusting rod, and the adjusting rod is in threaded connection with the cross rod through the external threads on the adjusting rod and the threaded through hole in the cross rod;
The thickness of the lower permeable stone (22) and the upper permeable stone (24) is 10mm;
the distance meter (62) adopts a laser distance meter.
7. The test method of the rock-soil body permeation deformation test device under the low-stress condition according to any one of claims 1 to 6, which is characterized by comprising the following specific steps:
s1, preparing a cylindrical rock-soil body sample (26), and performing core drilling, polishing and demolding on raw rock to prepare the cylindrical rock-soil body sample (26) required by a test;
s2, assembling a deformation amount testing system, namely brushing a layer of waterproof glue on the outer side wall of a cylindrical rock-soil body sample (26) and sleeving a first layer of elastic rubber membrane (23), then placing a water permeable stone (24), a round water permeable steel plate (27) and a round water impermeable steel plate (25) on the upper surface of the cylindrical rock-soil body sample (26), placing a lower water permeable stone (22) on the lower surface of the cylindrical rock-soil body sample (26), wrapping the lower water permeable stone (22) by the first layer of elastic rubber membrane (23), attaching the upper water permeable stone (24) to the round water permeable steel plate (27), and attaching the round water permeable steel plate (27) to the round water impermeable steel plate (25);
s3, confining pressure loading, namely sequentially sleeving a plurality of layers of elastic rubber films (23) on the outer side of the elastic rubber film (23) of the first layer so as to meet the requirement of applying designed confining pressure;
S4, loading vertical load, namely, snapping and fixing a steel ball at the lower end of a vertical loading rod (44) and a ball support on a round waterproof steel plate (25) through a hollow hemispherical groove of the steel ball support, and then placing a loading weight (46) for loading the design weight into a loading weight tray (45);
s5, performing permeation control, namely opening a first valve to enable water to flow through a water inlet pipe (33), sequentially flowing through a water suction pump (34), a pressure meter (32) and a circular water-impermeable steel plate (25), and controlling water pressure and water flow required by permeation through the pressure meter (32) and the first valve;
s6, dry and wet circulation control, namely firstly opening a first valve and a sixth valve to enable water flow to enter the lower portion of a circular water-impermeable steel plate (25), closing the first valve and the sixth valve when water flows out of an air pipe branch where the sixth valve is located, closing the fifth valve when the weight of water in a water collector (65) is unchanged, then opening a fourth valve and a vacuum pump (52), discharging air in a cylindrical rock-soil body sample (26), saturating the cylindrical rock-soil body sample (26), closing the fourth valve and the vacuum pump (52) after 24 hours, opening the second valve, the third valve and the air heater (51), enabling hot air to take away water through the cylindrical rock-soil body sample (26), entering a drying device (53) to dehumidify, closing the second valve and the air heater (51) until the cylindrical rock-soil body sample (26) is dried, and then opening the sixth valve to enable the dehumidified air to be discharged from the air pipe after passing through a water outlet pipe (28) and the cylindrical hot air sample (26), and the dry and wet air is a dry and wet circulation; repeating the step until the number of dry and wet circulation times required by the test is reached;
S7, deformation measurement and permeability coefficient monitoring, wherein the vertical deformation and the annular integral deformation are monitored through real-time reading of a dial indicator (61) and a range finder (62), and every other timetThe water collector (65) and the drying device (53) are weighed by an electronic balance (66) in a time period, the mass of the water collector is recorded, and the permeability coefficient is obtained by calculating the water quantity passing through the water outlet pipe (28) and the water quantity passing through the drying device (53) in unit time; and according to the axial pressure and the confining pressure loaded on the cylindrical rock-soil body sample (26), the vertical deformation and the annular integral deformation thereof, the change rule of the permeability coefficient under the action of different permeability pressures under the dry-wet circulation condition is obtained.
8. The method of testing a rock-soil body osmotic deformation test device under low stress conditions according to claim 7, wherein said cylindrical rock-soil body specimen (26) is in the form oftOsmotic coefficient over a period of timekThe determination is made according to the following equation:
；
in the method, in the process of the invention,dis the diameter of a cylindrical rock-soil body sample (26),Qfor the seepage through a cylindrical rock-soil body sample (26) after the osmotic pressure loading has stabilized,His the height of a cylindrical rock-soil body sample (26),Pis osmotic pressure, i.e. water pressure;
The osmotic flow rate through the cylindrical rock-soil body sample (26) after the osmotic pressure loading is stabilizedQThe determination is made according to the following equation:
；
in the method, in the process of the invention,for the initial weight of the water collector (65),/->For the initial weight of the drying means (53), ->Is loaded with the water collector (65)tWeight after time period stabilization, +.>Is loaded with a drying device (53)tWeight after time period stabilization;
when the water content of the drying device (53) is increased to 70% of the mass of the quicklime, the cylindrical rock-soil body sample (26) is considered to be dried, and the second valve and the air heater (51) are closed.
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| EP4191242A1 (en) * | 2021-12-02 | 2023-06-07 | Université Gustave Eiffel | Device and method to simulate wetting and drying in-situ conditions on a sample |
| CN114965224B (en) * | 2022-06-10 | 2023-03-03 | 东北林业大学 | Multifunctional rock-soil permeability coefficient measuring device and testing method |
| CN114942213B (en) * | 2022-07-25 | 2022-10-25 | 东北大学 | Asphalt concrete permeability coefficient testing device |
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