Wall-soil interaction force test method and test macro
Technical field
The present invention relates to wall-soil interaction Force meansurement, be specially a kind of method of testing measuring wall-soil interaction power (comprising earth pressure at rest, active earth pressure and passive earth pressure), and a kind of test macro realizing this method of testing.
Background technology
Wall-soil interaction problem is the important topic of the safety and stablization being related to the engineerings such as landslide, side slope, foundation ditch, and research wall-soil interaction power (i.e. soil pressure) is the main path of research Soil-structure interaction model problem.According to the stress equilibrium state after wall residing for the soil body, the soil pressure acting on the wall back of the body can be divided into earth pressure at rest, active earth pressure and passive earth pressure three kinds.
Earth pressure at rest (earthpressureatres) refers to when under the thrust of retaining wall at rolling earth behind retaining wall, when not producing any movement or rotate, after wall, the soil body does not destroy, but is in elastic equilibrium stress state, and the soil pressure now acting on wall back is called earth pressure at rest.
Active earth pressure (activeearthpressure) refers to that retaining wall deviates from earth fill to when moving or rotate under soil pressure effect, after wall, the soil body has falling tendency due to side restricted the loosening of institute, glide for stoping it, shear stress on slipping plane potential in the soil body will increase gradually, thus the soil pressure acting on wall back is reduced gradually, when the movement of wall or rotation reach certain numerical value, shear stress on slipping plane equals soil classifiction, after wall, the soil body reaches initiatively state of limit equilibrium, the soil pressure now acting on wall back reaches minimum value, be called active earth pressure.
Passive earth pressure (passiveearthpressure) refers to that retaining wall is under the effect of external force, when moving towards the direction of banketing or rotate, after wall, the soil body is owing to being squeezed, there is the trend of upper cunning, sliding for stoping on it, shear stress in the soil body on slipping plane oppositely increases, the soil pressure acting on wall back is increased gradually, when the amount of movement of wall is enough large, shear stress on slipping plane equals shearing strength again, after wall, the soil body reaches passive state of limit equilibrium, and the soil pressure at this moment acting on wall back reaches maximal value, is called passive earth pressure.
In Practical Project, stress state due to the soil body after wall is not often elastic equilibrium stress state, initiatively limiting equilibrium stress state or passive limiting equilibrium stress state, and therefore the soil pressure acting on the wall back of the body is also often not equal to earth pressure at rest, active earth pressure or passive earth pressure.When determining the sense of displacement of the soil body after retaining wall is relative to wall, the magnitude range residing for soil pressure is confirmable.When wall is to the displacement of soil body direction, act on the soil pressure size of the wall back of the body between earth pressure at rest and passive earth pressure; When wall is away from the displacement of soil body direction, act on the soil pressure size of the wall back of the body between active earth pressure and earth pressure at rest.Visible, earth pressure at rest, active earth pressure and passive earth pressure are three eigenwerts of soil pressure size, correctly determine their size and distribute most important to research wall-soil interaction problem.
The indoor test method of soil pressure always pay close attention to by people.The indoor test method of earth pressure at rest is mainly divided into compressometer method and triaxial apparatus method, is namely measured the static lateral pressure coefficient of the soil body by shop experiment, and then for calculating earth pressure at rest; The indoor test method mainly triaxial (test) method of active earth pressure and passive earth pressure, namely by the triaxial test determination soil body have the initiative limiting equilibrium stress state or passive limiting equilibrium stress state time the plane of fracture, and then determine coefficient of active earth pressure or coefficient of passive earth pressure, for calculating active earth pressure or passive earth pressure.The theory of indoor test method institute foundation is tight and measuring accuracy is high, but due to specimen size very little, only can meet the earth pressure test of fine grained soil.
In order to overcome the deficiency of soil pressure shop experiment method of testing, there has been proposed the simulation test method of testing of soil pressure.Existing analogy method can simulate active earth pressure and the passive earth pressure of the soil body respectively, can realize the simulation of the soil-structure interactions to vast scale preloading.As seen from the open technique, after test pit fills the soil body, passive earth pressure or active earth pressure can be tested, and disposablely can not complete the test of test passive earth pressure and active earth pressure.If desired record passive earth pressure and active earth pressure, then need, after recording a kind of soil pressure, first to cut out the soil body in test pit, and then constructing soil body examination obtains another soil pressure again.As everyone knows, it is completely the same that the soil body filled for twice is difficult to guarantee in its homogeneity, packing, water percentage etc., and its mechanical characteristic index also can not be identical, and this is disadvantageous to comparative analysis passive earth pressure and active earth pressure test findings.Moreover the method still can not test earth pressure at rest.Visible, at present about the simulation test method of testing also Shortcomings part of soil pressure.
In addition, wall-soil interaction power is by the impact of several factors, and the principal element that forefathers have paid close attention to comprises the distribution of soil body surface load after the physico mechanical characteristic of the soil body, the smooth degree of the wall back of the body, the displacement mode of wall and size, wall and size etc.Except these influence factors, the drying and watering cycle effect etc. still having the seepage state of underground water, the wall-drainage pattern of soil series system, atmospheric precipitation, the soil body to stand also affects size and the distribution of wall-soil interaction power, and these factors may be extremely important sometimes.Such as, after large reservoir impounding and operation, reservoir level and underground water table change in periodically rising, declining with reservoir operation, the littoral soil body in its variation range is made to stand periodic drying and watering cycle effect and groundwater seepage effect, now, drying and watering cycle effect and groundwater seepage effect just may become the key factor affecting wall-soil interaction power.Existing wall-soil interaction force test method and proving installation still can not be used for the wall-soil interaction power problem studying the complex condition such as drying and watering cycle effect, groundwater seepage effect.
Summary of the invention
The object of this invention is to provide a kind of method measuring retaining wall and soil body acting force.
The technical scheme adopted for realizing the object of the invention is such, and a kind of wall-soil interaction force test method, comprises the following steps:
1) prepare rectangular parallelepiped soil sample, the length of described rectangular parallelepiped soil sample, height, be widely respectively L, H, W, in described rectangular parallelepiped soil sample, area is that two sides of L × H are respectively leading flank and trailing flank, and area is that two sides of H × W are respectively left side and right side; In addition, surface area is upper surface and the lower surface that two faces of L × W are respectively rectangular parallelepiped soil sample.
2) left side of described rectangular parallelepiped soil sample contacts with left wallboard, and described left wallboard side connects with the expansion link of horizontal loading apparatus I, opposite side contacts with described left side; The right side of described rectangular parallelepiped soil sample contacts with right wallboard, and described right wallboard side connects with the expansion link of horizontal loading apparatus II, opposite side contacts with described right side;
3) simultaneously or carry out a) in no particular order and b) operate:
A) active earth pressure is tested: make the displacement that described left wallboard or right wallboard occur away from soil sample direction, the displacement of monitoring wallboard, monitor wall-soil interaction power, after determining wall there is overall prerupture wall-soil interaction power minimum value in the soil body, is active earth pressure simultaneously;
B) passive earth pressure is tested: the displacement making left wallboard or the close soil sample direction of right wallboard generation be not subjected to displacement a), monitor the displacement of wallboard, monitor wall-soil interaction power simultaneously, after determining wall there is overall prerupture wall-soil interaction power maximal value in the soil body, is passive earth pressure.
As preferably, described L>5H.
Step 2 according to actual needs) in, simulate described rectangular parallelepiped soil sample and stand underground water immersion, seepage action of ground water, drying and watering cycle effect, rainfall or surface load.
According to actual needs, before step 3) starts, test earth pressure at rest, namely when the displacement relative to described rectangular parallelepiped soil sample does not occur for described left wallboard and right wallboard, test wall-soil interaction power, is earth pressure at rest.
Another object of the present invention is open a kind of wall-soil interaction force test system, and this system can realize said method.
I.e. wall-soil interaction force test system, comprises the base plate with upper horizontal surface, and during experiment, the upper surface of described base plate carries tested soil sample.
Described tested soil sample is long, high, the wide rectangular parallelepiped soil sample being respectively L, H, W, and in described rectangular parallelepiped soil sample, area is that two sides of L × H are respectively leading flank and trailing flank, and area is that two sides of H × W are respectively left side and right side.
The upper surface of described base plate installs front side board, back side panel, left plate and right plate
,the side of described front side board contacts with the leading flank of tested soil sample, and the side of described back side panel contacts with the trailing flank of tested soil sample, and the side of described left plate contacts with the left side of tested soil sample, and the side of described right plate contacts with the right side of tested soil sample.
The height of described front side board and back side panel is more than or equal to H, and the height of described left plate and right plate is less than H.The left wallboard of upper ends of described left plate, the side of described left wallboard contacts with the left side of tested soil sample, another side to the left side reaction frame being fixed on plate upper surface, horizontal loading apparatus I is installed between described left side reaction frame and left wallboard.
The right wallboard of upper ends of described right plate, the side of described right wallboard contacts with the right side of tested soil sample, another side to the right side reaction frame being fixed on plate upper surface, horizontal loading apparatus II is installed between described right side reaction frame and right wallboard.
The side that described front side board and/or back side panel contact with tested soil sample is provided with soil pressure sensor and pore water pressure sensor.The side that described left wallboard contacts with tested soil sample with right wallboard is provided with soil pressure sensor and pore water pressure sensor.
Further, the upper surface of described base plate lays percolation path, and described percolation path is the permeable floral tube of S type.
Further, described base plate has some osculums, the valvular drainpipe of described osculum connecting band.
Further, the top of described base plate has crossbeam, and described crossbeam lower end connects vertical loading device, and the expansion link of described vertical loading device connects the upper surface of load plate, and during experiment, the lower surface of described load plate contacts with the upper surface of tested soil sample.
Advantage of the present invention is:
1) after a sample preparation, earth pressure at rest, active earth pressure and passive earth pressure can be recorded respectively.
2) before test wall-soil interaction power, soil sample can be made first to stand underground water immersion, seepage action of ground water, drying and watering cycle effect, rainfall, surface load or other effect, simulate the actual state of retaining wall truly.
Accompanying drawing explanation
The nonlimiting examples that device of the present invention can be provided by accompanying drawing further illustrates.
Fig. 1 is test method schematic diagram of the present invention;
Fig. 2 is the stereographic map of present system;
Fig. 3 is the front view of present system;
Fig. 4 is the side view of present system;
Fig. 5 is the vertical view of present system;
Fig. 6 is front view inside the left and right wallboard of present system;
Fig. 7 is front view outside the left and right wallboard of present system;
Fig. 8 is the forward and backward side plate interior sides front view of present system;
Fig. 9 is one embodiment of the invention experimental result coordinate analysis figure.
In figure: 1-base plate, the tested soil sample of 2-, 3-front side board, 4-back side panel, 7-left plate, 8-right plate, the left wallboard of 9-, the right wallboard of 10-, reaction frame on the left of 11-, reaction frame on the right side of 12-, 13-horizontal loading apparatus I, 14-horizontal loading apparatus II, 15-load plate, 17-crossbeam, 18-vertical loading device, 19-support, 20-percolation path, 21-rising pipe, 22-water tank.
Embodiment
Below in conjunction with drawings and Examples, the invention will be further described, but should not be construed the above-mentioned subject area of the present invention and be only limitted to following embodiment.Without departing from the idea case in the present invention described above, according to ordinary skill knowledge and customary means, make various replacement and change, all should be included in the scope of the present invention.
embodiment 1:
The present embodiment discloses a kind of wall-soil interaction force test method, comprises the following steps:
1) prepare rectangular parallelepiped soil sample, i.e. tested soil sample, the length of described rectangular parallelepiped soil sample, height, be widely respectively L, H, W, in described rectangular parallelepiped soil sample.In order to define each face of tested soil sample, in the present embodiment, the surface area of tested soil sample is that to be respectively leading flank and trailing flank, surface area be that to be respectively left side and right side, surface area be upper surface and the lower surface that two faces of L × W are respectively rectangular parallelepiped soil sample for two sides of H × W for two sides of L × H.
2) left side of described rectangular parallelepiped soil sample contacts with left wallboard, and described left wallboard side connects with the expansion link of horizontal loading apparatus I, opposite side contacts with described left side; The right side of described rectangular parallelepiped soil sample contacts with right wallboard, and described right wallboard side connects with the expansion link of horizontal loading apparatus II, opposite side contacts with described right side; In the present embodiment, left wallboard and right wallboard can without Frictional Slipping.Described left wallboard side connects with the expansion link of horizontal loading apparatus I, opposite side contacts with described left side, and described right wallboard side connects with the expansion link of horizontal loading apparatus II, opposite side contacts with described right side.The horizontal loading apparatus I of the present embodiment comprises by the flexible expansion link of hydraulic means control, and the telescopic end of described expansion link is connected with left wallboard, can apply pulling force or thrust to left wallboard.The structure of described horizontal loading apparatus II is identical with the structure of horizontal loading apparatus I, and only the telescopic end of the expansion link of horizontal loading apparatus II is connected with right wallboard, can applies pulling force or thrust to right wallboard.
3) the present embodiment comprise following a) and b), a) and b) can or carry out in no particular order simultaneously.
In the present embodiment, first carry out a), then carry out b) namely:
A) active earth pressure is tested: make the displacement that described left wallboard or right wallboard occur away from soil sample direction, the displacement of monitoring wallboard, monitor wall-soil interaction power, after determining wall there is overall prerupture wall-soil interaction power minimum value in the soil body, is active earth pressure simultaneously;
B) passive earth pressure is tested: the displacement making left wallboard or the close soil sample direction of right wallboard generation be not subjected to displacement a), monitor the displacement of wallboard, monitor wall-soil interaction power simultaneously, after determining wall there is overall prerupture wall-soil interaction power maximal value in the soil body, is passive earth pressure.
Further, in the present embodiment, described L>5H, and H=W, namely described left side and right side are square.
In the present embodiment, in step 2) in, namely rectangular parallelepiped soil sample is after the production, simulates described rectangular parallelepiped soil sample and stands underground water immersion, seepage action of ground water, drying and watering cycle effect, rainfall or surface load.
Further, step 2) terminate after, before step 3) starts, test earth pressure at rest, namely when the displacement relative to described rectangular parallelepiped soil sample does not occur for described left wallboard and right wallboard, test wall-soil interaction power, is earth pressure at rest.
embodiment 2:
The present embodiment provides a kind of wall-soil interaction force test system, and this system can realize method described in embodiment 1.Particularly, this system comprises the base plate 1 with upper horizontal surface, and during experiment, the upper surface of described base plate 1 carries tested soil sample 2.
In the present embodiment, described tested soil sample 2 can be rectangular parallelepiped soil sample described in embodiment 1, is long, high, the wide rectangular parallelepiped soil sample being respectively L, H, W.In described rectangular parallelepiped soil sample, area is that two sides of L × H are respectively leading flank and trailing flank, and area is that two sides of H × W are respectively left side and right side.
The upper surface of described base plate 1 installs front side board 3, back side panel 4, left plate 7 and right plate 8, left wallboard 9 is installed in the upper end of described left plate 7, right wallboard 10 is installed in the upper end of described right plate 8, described front side board 3, back side panel 4, the lower end of left plate 7 and right plate 8 is all fixedly connected on the upper surface of base plate 1, i.e. front side board 3, back side panel 4, left plate 7, right plate 8, left wallboard 9 and right wallboard 10 are spliced into a rectangular box, form one after the bottom of described rectangular box and base plate 1 combine and hold tested soil sample 2(rectangular parallelepiped soil sample), the cell body (test flume) that upper end is uncovered, described front side board 3, back side panel 4, left plate 7, right plate 8 is all fixedly connected with base plate 1 junction.Described front side board 3, back side panel 4, left plate 7, right plate 8, left wallboard 9 and right wallboard 10 are inner side towards the side at cell body center.In the present embodiment, test flume is put into after tested soil sample 2 can being made, also tested soil sample 2 can directly be prepared in test flume, which kind of no matter with place, recording active earth pressure, passive earth pressure and earth pressure at rest, and satisfy in water-process such as drainage, infiltration in simulation soil sample, no longer shift out or change soil sample, avoiding stirring the soil body.
In embodiment, tested soil sample 2 will be prepared in test flume after, the side (inner side) of described front side board 3 contacts with the leading flank of tested soil sample 2, the side (inner side) of described back side panel 4 contacts with the trailing flank of tested soil sample 2, the side (inner side) of described left plate 7 contacts with the left side of tested soil sample 2, the side (inner side) of described right plate 8 contacts with the right side of tested soil sample 2, the side (inner side) of described left wallboard 9 contacts with the left side of tested soil sample 2, and the side (inner side) of described right wallboard 10 contacts with the right side of tested soil sample 2.The height of described front side board 3 and back side panel 4 is more than or equal to H, and the height of described left plate 7 and right plate 8 is less than H, and the height of described left wallboard 9 and right wallboard 10 is less than H.As preferably, the front side board 3 of the present embodiment and the height of back side panel 4 equal H, and the height of left plate 7 and right plate 8 is H × 1/10 ~ H × 2/5, and the height of left wallboard 9 and right wallboard 10 is for being less than H × 3/5 ~ H × 9/10.
The left wallboard 9 of upper ends of described left plate 7, the side of described left wallboard 9 contacts with the left side of tested soil sample 2, another side to the left side reaction frame 11 of upper surface being fixed on base plate 1, between described left side reaction frame 11 and left wallboard 9, horizontal loading apparatus I 13 is installed.The horizontal thrust that described horizontal loading apparatus I 13 can apply towards tested soil sample 2 one side to left wallboard 9, also can apply the horizontal pull of tested soil sample 2 one side dorsad to left wallboard 9, namely can make left wallboard 9 occur with tested soil sample 2 in opposite directions or reverse motions.
In the present embodiment, horizontal loading apparatus I 13 can adopt hydraulic loading device, namely comprises a hydraulic cylinder I and expansion link I, and described hydraulic cylinder is fixed on the reaction frame 11 of left side, described expansion link I one end is in hydraulic cylinder I, and the other end is connected to an end face of left wallboard 9.Further, also have the device measuring pulling force that horizontal loading apparatus I 13 applies left wallboard or thrust size, this device can be mounted in the mechanics sensor between described expansion link I and left wallboard 9.Further, see Fig. 7, in order to keep the steadily movement of loading procedure deadlight, three horizontal loading apparatus I 13 are at least installed between described left side reaction frame 11 and left wallboard 9, namely there are few three load(ing) points.
The right wallboard 10 of upper ends of described right plate 8, the side of described right wallboard 10 contacts with the right side of tested soil sample 2, another side reaction frame 12 to the right, the lower end of described right side reaction frame 12 is fixedly connected with the upper surface of base plate 1, installs horizontal loading apparatus II 14 between described right side reaction frame 12 and right wallboard 10.The horizontal thrust that described horizontal loading apparatus II 14 can apply towards tested soil sample 2 one side to right wallboard 10, also can apply the horizontal pull of tested soil sample 2 one side dorsad to right wallboard 10, namely can make right wallboard 10 that the contrary or move toward one another with tested soil sample 2 occurs.In the present embodiment, horizontal loading apparatus II 14 can adopt hydraulic loading device, namely comprises a hydraulic cylinder II and expansion link II, and described hydraulic cylinder II is fixed on the reaction frame 12 of right side, described expansion link II one end is in hydraulic cylinder II, and the other end is connected to an end face of right wallboard 10.Further, also have the device measuring pulling force that horizontal loading apparatus II 14 applies right wallboard 10 or thrust size, this device can be mounted in the mechanics sensor between described expansion link II and right wallboard 10.Further, see Fig. 7, in order to keep the steadily movement of loading procedure deadlight, three horizontal loading apparatus II 14 are at least installed between described right side reaction frame 12 and right wallboard 10, namely there are few three load(ing) points.
Further, for reducing the friction between the upper end of left plate 7 and the lower end of left wallboard 9, embed some balls at left wallboard 9 with left plate 7 surface of contact.In like manner also embed some balls at right wallboard 10 with right plate 8 surface of contact.
What deserves to be explained is, right wallboard 10 does not all contact with base plate 1 with the lower end of left wallboard 9.When right wallboard 10 and left wallboard 9 occur relative to tested soil sample 2 mobile, tested soil sample 2 can be destroyed.To be fixedly connected with base plate 1 due to left plate 7 and right plate 8 and there is certain altitude, the failure mechanics this ensures that thering tested soil sample 2 is in inside soil body, and not at the surface of contact of tested soil sample 2 with base plate 1, avoid friction between tested soil sample 2 and base plate to the interference of experimental result.
The side that described front side board 3 and/or back side panel 4 contact with tested soil sample 2 is provided with soil pressure sensor and pore water pressure sensor.The side that described left wallboard 9 contacts with tested soil sample 2 with right wallboard 10 is provided with soil pressure sensor and pore water pressure sensor.
In the present embodiment, described soil pressure sensor measures the amount of force between wall soil.Further, described soil pressure sensor embeds in wallboard and side plate, avoids the friction between sensor body and tested soil sample 2.See Fig. 6 or Fig. 8, the side of wallboard and side plate has some soil pressure sensors, in experimentation, each soil pressure sensor can measure the acting force between this wall soil, and can obtain the acting force comparatively accurately between wall soil by the measurement result recording multiple soil pressure sensor.
In like manner described pore water pressure sensor measures the water pressure size of wall soil contact face.Further, described pore water pressure sensor embeds in wallboard and side plate, avoids the friction between sensor body and tested soil sample 2.See Fig. 6 or Fig. 8, the side of wallboard and side plate has some pore water pressure sensors, in experimentation, each pore water pressure sensor can measure the water pressure of this point, and can be obtained the water pressure of wall soil contact face comparatively accurately by the measurement result recording multiple pore water pressure sensor.
In the present embodiment, the effects such as underground water immersion, seepage action of ground water, drying and watering cycle effect or rainfall are stood in order to simulate tested soil sample 2, percolation path 20 is laid at the upper surface of described base plate 1, tested soil sample 2 is placed in after on base plate 1, between the upper surface of base plate 1 and the lower surface of tested soil sample 2, there is percolation path 20.In the present embodiment, described percolation path 20 is the permeable floral tube of S type, i.e. the tube wall of percolation path 20 has some apopores.Further, also comprise water tank 22, the elevation of water in described water tank 22 is controlled, and the rising pipe 21 bottom described water tank 22 is communicated with the water inlet of described percolation path 20.
Further, described base plate 1 has some osculums, the valvular drainpipe of described osculum connecting band.Namely make tested soil sample 2 be placed in after on base plate 1, the ponding in tested soil sample 2 can be discharged by base plate 1.
In the present embodiment, stand the effect of preloading in order to simulate tested soil sample 2, the top of described base plate 1 has crossbeam 17.In the present embodiment, the support 19 of upper surface that described crossbeam 17 can be fixed on bottom 1 by lower end supports, and makes crossbeam 17 suspension frame be located at the top of tested soil sample 2.Described crossbeam 17 lower end connects vertical loading device 18, and the expansion link of described vertical loading device 18 connects the upper surface of load plate 15, and during experiment, the lower surface of described load plate 15 contacts with the upper surface of tested soil sample 2.By the propulsion system in vertical loading device 18 to expansion link applying pressure straight down, load plate 15 is made to apply pressure to the upper surface of tested soil sample 2.
embodiment 3:
The present embodiment adopts system described in embodiment 2 to carry out wall-soil interaction Force meansurement experiment.
1) at base plate 1, front side board 3, back side panel 4, left plate 7 and right plate 8, and the tested soil sample 2 of preparation rectangular parallelepiped is empirically required in the rectangular parallelepiped experimental tank that jointly surrounds of left wallboard 9 and right wallboard 10.Described base plate 1, front side board 3, back side panel 4, left plate 7 and right plate 8 contact with each other face compact siro spinning technology, waterproof.Described left wallboard 9 and right wallboard 10 and tested soil sample 2 liang of end in contact.Load plate 15 is laid at the upper surface of tested soil sample 2.The upper end of described load plate 15 contacts with the expansion link of vertical loading device 18, lower end contacts with the upper surface of tested soil sample 2.
2) ~ e is carried out a)) wherein jump procedure 3 after one or more operation):
A) simulate described rectangular parallelepiped soil sample and stand underground water action of soaking: bottom tested soil sample 2, injected the water with certain pressure by the percolation path 20 bottom tested soil sample 2, close the valve of drainpipe simultaneously.The hydraulic pressure of percolation path 20 can be controlled by the elevation of water of regulating tank 22.Record hole pressure by the pore water pressure sensor on wallboard or side plate, record water level and the soaking time of tested soil sample 2.
B) simulate described rectangular parallelepiped soil sample and stand seepage action of ground water effect: bottom tested soil sample 2, inject the water with certain pressure or the valve opening drainpipe by the percolation path 20 bottom tested soil sample 2 and discharge water in tested soil sample 2.The hydraulic pressure of percolation path 20 can be controlled by the elevation of water of regulating tank 22.Record hole pressure by the pore water pressure sensor on wallboard or side plate, record water level and the Seepage flow time of tested soil sample 2.
C) simulate described rectangular parallelepiped soil sample and stand drying and watering cycle effect: bottom tested soil sample 2, injected the water with certain pressure by the percolation path 20 bottom tested soil sample 2, the valve opening drainpipe afterwards discharges the water in tested soil sample 2, and so circulate several times.The hydraulic pressure of percolation path 20 can be controlled by the elevation of water of regulating tank 22.Record hole pressure by the pore water pressure sensor on wallboard or side plate, record the water level of tested soil sample 2 and drying and watering cycle time, number of times.
D) simulate described rectangular parallelepiped soil sample and stand rainfall: to the upper surface trickle of tested soil sample 2, open or do not open the valve of drainpipe.Record hole pressure by the pore water pressure sensor on wallboard or side plate, record the water level of tested soil sample 2.
E) simulate described rectangular parallelepiped soil sample and stand surface load: the acting force applying straight down to load plate 15 by the expansion link of charger 18, described load plate 15 applies Loading to the upper end of tested sample 2.
3) test earth pressure at rest: when the displacement relative to described rectangular parallelepiped soil sample does not occur for described left wallboard and right wallboard, test wall-soil interaction power, is earth pressure at rest.
4) active earth pressure is tested: make described left wallboard generation away from the displacement in soil sample direction, the displacement of monitoring wallboard, monitor wall-soil interaction power, after determining wall there is overall prerupture wall-soil interaction power minimum value in the soil body, is active earth pressure simultaneously;
5) test passive earth pressure: the displacement near soil sample direction occurs right wallboard, monitors the displacement of right wallboard, monitors wall-soil interaction power simultaneously, after determining wall there is overall prerupture wall-soil interaction power maximal value in the soil body, is passive earth pressure.
Above-mentioned steps 4) and 5) can carry out simultaneously or carry out in no particular order.
See in Fig. 9, figure, horizontal ordinate represents the displacement S of wallboard, and ordinate represents pressure E, (E between body of wall and the soil body
0, 0) and the ordinate E that puts
0namely the earth pressure at rest that above-mentioned experiment records, (E is represented
p, S
p) the ordinate E that puts
pnamely the passive earth pressure that above-mentioned experiment records, (E is represented
a, S
a) the ordinate E that puts
anamely the active earth pressure that above-mentioned experiment records is represented.