CN112649304A - System and method for testing load performance of assembled reinforced retaining wall - Google Patents

System and method for testing load performance of assembled reinforced retaining wall Download PDF

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CN112649304A
CN112649304A CN202011516456.5A CN202011516456A CN112649304A CN 112649304 A CN112649304 A CN 112649304A CN 202011516456 A CN202011516456 A CN 202011516456A CN 112649304 A CN112649304 A CN 112649304A
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retaining wall
test
load
reinforced
reinforced retaining
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王家全
侯森磊
林志南
黄世斌
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Guangxi University of Science and Technology
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Guangxi University of Science and Technology
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
    • G01N3/10—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces generated by pneumatic or hydraulic pressure
    • G01N3/12—Pressure testing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/02—Details
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0001—Type of application of the stress
    • G01N2203/0003—Steady
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0014—Type of force applied
    • G01N2203/0016—Tensile or compressive
    • G01N2203/0019—Compressive
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/003—Generation of the force
    • G01N2203/0042—Pneumatic or hydraulic means
    • G01N2203/0048—Hydraulic means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0058—Kind of property studied
    • G01N2203/006—Crack, flaws, fracture or rupture
    • G01N2203/0062—Crack or flaws
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0058—Kind of property studied
    • G01N2203/0069—Fatigue, creep, strain-stress relations or elastic constants
    • G01N2203/0075—Strain-stress relations or elastic constants
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/06—Indicating or recording means; Sensing means
    • G01N2203/067—Parameter measured for estimating the property
    • G01N2203/0676—Force, weight, load, energy, speed or acceleration
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/06—Indicating or recording means; Sensing means
    • G01N2203/067—Parameter measured for estimating the property
    • G01N2203/0682—Spatial dimension, e.g. length, area, angle

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
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  • Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)

Abstract

The invention discloses an assembled reinforced retaining wall load performance test system and a test method, which comprises a test model box, a load loading device and data acquisition equipment for acquiring deformation quantity of a reinforced retaining wall after being loaded, wherein the test model box is provided with an upper side opening and at least one peripheral side opening, the reinforced retaining wall is arranged in the test model box, and the reinforced retaining wall is positioned at the peripheral side opening; the load loading device can apply vertical load to the reinforced retaining wall in the test model box from the opening at the upper side. The test system can effectively simulate and measure the change of the reinforced retaining wall structure under dynamic and static loads, and is easy to test; the test method is convenient to operate, and can simplify the whole measurement data of dynamic and static load simulation and obtain the accurate data of the load test.

Description

System and method for testing load performance of assembled reinforced retaining wall
Technical Field
The invention relates to the field of reinforced retaining walls, in particular to a system and a method for testing the load performance of an assembled reinforced retaining wall.
Background
At present, a reinforced earth retaining wall structure is used as an effective flexible reinforcing roadbed retaining structure for highways, railways, abutment platforms and side slopes, and mainly needs to bear the effects of static load and dynamic load. The static load is mainly generated by the earth pressure of the filling behind the retaining wall and the gravity of the overlying structure on the retaining wall structure, and the dynamic load is mainly generated by the action of traffic load or earthquake load on the surface layer of the foundation, dynamic load caused by natural factors and the like on the retaining wall. The former is related to the structural form, filling property and overlying structural facilities of the reinforced retaining wall, and the latter is mainly related to the service environment of the reinforced retaining wall and the factors of the loading capacity, speed, driving position and the like of the vehicle.
In recent years, many scholars at home and abroad often study and discuss the structure of the reinforced retaining wall through on-site or indoor model tests, theoretical analysis, numerical simulation and the like, so that the development of the reinforced earth technology is continuously promoted. The indoor model test is an effective research method for replacing a prototype test according to a certain geometric proportion, a reliable test result can be monitored by controlling external conditions and natural conditions, meanwhile, the accuracy of corresponding theoretical research and numerical simulation analysis can be verified, and the method is also an effective method for researching or solving a plurality of difficult and complicated problems in the field of geotechnical engineering. Compared with an indoor model test, the field test is difficult to seek for proper actual engineering, and even if the field test can be carried out, the field test is influenced by a plurality of factors and is difficult to avoid one by one, so that the data obtained by monitoring cannot be completely reliable; the numerical simulation and theoretical analysis research process is very complex, and more parameters are difficult to be accurate and simplified, so that the method has certain limitations. Therefore, it is necessary to develop a test platform for an assembled reinforced retaining wall and an effective test method for simulating and measuring the change of the assembled reinforced retaining wall structure under dynamic and static loads so as to accurately obtain a real numerical value.
Disclosure of Invention
The invention aims to solve at least one of the technical problems mentioned above, and provides a reinforced retaining wall test system and a test method, wherein the test system can effectively simulate and measure the change of a reinforced retaining wall structure under dynamic and static loads, and is easy to test; the test method is convenient to operate, and can simplify the whole measurement data of dynamic and static load simulation and obtain the accurate data of the load test.
In order to achieve the purpose, the invention adopts the technical scheme that:
the utility model provides an assembled reinforced retaining wall load performance test system, includes:
the test model box is provided with an upper side opening and at least one peripheral side opening, a reinforced retaining wall is arranged in the test model box, and the reinforced retaining wall blocks the peripheral side opening;
the load loading device can apply vertical load to the reinforced retaining wall in the test model box from the upper opening and measure the settlement of the reinforced retaining wall in the vertical direction; and
and the data acquisition equipment is used for acquiring the deformation of the reinforced retaining wall after the reinforced retaining wall is loaded.
As the improvement of the technical scheme, the reinforced retaining wall comprises a retaining wall panel, one end of the retaining wall panel is fixed on the inner side of the retaining wall panel through plugging, and the filler is coated outside the rib, wherein the blocking is arranged at the opening of the peripheral side of the retaining wall panel, and the rib is provided with at least one layer.
As an improvement of the above technical solution, the data acquisition device comprises
The flexible displacement meter is arranged on the rib and used for measuring the deformation amount of the rib after the load is applied to the rib;
the displacement sensor is arranged on the opening on the peripheral side, can slide relative to the retaining wall panel and is used for measuring the horizontal displacement and the settlement in the vertical direction of the loaded retaining wall panel;
the accelerometer is arranged in the filler and is used for measuring the acceleration amount of the embedded part after being loaded;
and the soil pressure box is arranged in the filler and is used for measuring the soil pressure after the buried part is loaded.
As the improvement of the technical scheme, the test model box is provided with a mounting frame on the outer side of one side of the opening on the peripheral side, the displacement sensor is installed on the mounting frame, the mounting frame is not contacted with the retaining wall panel, and the displacement sensor is abutted to the retaining wall panel.
As the improvement of the technical scheme, the test model box comprises a base and a frame, wherein the frame is installed on the base, a rear steel plate is arranged on one side, opposite to the opening on the peripheral side, of the frame, and a side steel plate and a glass fiber reinforced plastic panel are correspondingly arranged on two sides, opposite to the opening on the peripheral side, of the frame respectively.
As an improvement of the above technical scheme, the load loading device comprises a reaction frame, a hydraulic cylinder with an output end downwards arranged on the reaction frame, and a loading plate arranged on the output end of the hydraulic cylinder, wherein the hydraulic cylinder can apply vertical load to the reinforced retaining wall in the test model box through the loading plate.
As an improvement of the technical scheme, the device also comprises a digital image testing system, wherein the digital image testing system comprises a digital camera and an image acquisition and analysis computer, and a transparent glass fiber reinforced plastic panel is arranged on one side of the test model box, which is provided with openings on the peripheral side; the digital camera and the image acquisition and analysis computer are both arranged on one side of the glass fiber reinforced plastic panel, the digital camera can acquire deformation displacement picture information of the filler around different layers of the reinforced materials, and the image acquisition and analysis computer can receive image information shot by the digital camera and calculate and draw a displacement cloud picture and a strain field of the filler layer near the interface of any layer of the reinforced materials and the filler.
A method for testing the load performance of an assembled reinforced retaining wall comprises the following steps:
step 1, preparing test equipment, preparing a test model box, a load loading device and data acquisition equipment, and debugging the load loading device and the data acquisition equipment until the preset requirements are met;
step 2, constructing a test unit layer, filling and compacting filler and a rib material in a test model box layer by layer, mounting a flexible displacement meter on the rib material, embedding an accelerometer and a soil pressure cell in the filler according to a preset position, and building a retaining wall panel consisting of assembly modules at peripheral side openings so that the rib material is connected with the retaining wall panel consisting of the assembly modules; mounting a displacement sensor which can be fixed relative to the position of the test model box on a retaining wall panel formed by the assembly type module;
step 3, constructing a reinforced retaining wall, and filling test unit layers layer by layer according to the mode of the step 2 until a preset test height is reached and the reinforced retaining wall is formed;
step 4, mounting a loading plate, leveling the upper surface of the uppermost test unit layer of the reinforced retaining wall by using a horizontal ruler after the reinforced retaining wall is filled, and then placing the loading plate on a preset pressure testing point of the uppermost test unit layer;
step 5, a loading test is carried out, data acquisition equipment is debugged, the test time of each measurement is unified, and a load loading device carries out loading in a sine wave type loading mode until the reinforced retaining wall is damaged; recording each measurement data in the data acquisition equipment during the test; the digital camera obtains the deformation displacement picture information of the filler around different layers of the reinforced materials, the image acquisition and analysis computer can receive the image information shot by the digital camera and calculate and draw a displacement cloud picture and a strain field of the filler layer near the interface of any layer of the reinforced materials and the filler; the applied sinusoidal excitation force is expressed as follows:
P＝P0+PAsin(2πft)
in the formula, P0Is the load constant (kN);
PAis the dynamic load amplitude (kN);
f is the loading frequency (Hz);
t is time(s);
and 6, ending the test, and shooting the accumulated deformation conditions of the top layer loading plate and the retaining wall panel of the reinforced retaining wall and recording the number of cracks by using a high-definition digital camera after the reinforced retaining wall is damaged.
As an improvement of the above technical solution, the specific loading manner in step 5 is as follows: the load loading device applies static load pressurization to a preset dynamic load central value step by step from zero, the load loading device (3) applies static load pressurization to a preset dynamic load central value P step by step from zero0Each stage is loaded with nkN, n is a natural integer; then respectively and sequentially applying a dynamic load value P0±nkN、P0±2nkN、P0±3nkN、P0±4nkN、P0±5nkN、P06nkN, load duration per stageThe time is 5-10min until the test is finished when the retaining wall is damaged.
As an improvement of the above technical solution, the step 2 includes the steps of:
step 2.1, filling and compacting fillers in a test model box in a layered mode, and building retaining wall panels formed by assembled modules at openings on the peripheral sides, wherein the filling thickness of each test unit layer is 10-12 cm, and the height of the retaining wall is 110-144 cm; in the filling process, an electric flat plate compactor is adopted to level and compact the filler for 3-5 times, and then a weight of 15-30 kg is used to compact the filler on a unit area, wherein the compaction frequency per unit area is 4-7 times; gradually adding the filler in the flattening process until the compaction thickness of the test unit layer is 12-16 cm, and the compaction coefficient is more than 95%;
step 2.2, paving a rib material on the compacted test unit layer according to a preset specification, wherein one end of the rib material is connected with a retaining wall panel formed by the assembly type module; mounting a flexible displacement meter on the rib, and embedding an accelerometer and a soil pressure cell in the test unit layer;
and 2.3, fixedly mounting a displacement sensor on the mounting frame outside the opening on the peripheral side, wherein the displacement sensor is abutted against the outer side of the retaining wall panel formed by the assembled module.
As an improvement of the above technical solution, the filler in step 2.1 is medium sand with good grain composition.
Compared with the prior art, the beneficial effects of this application are:
according to the load performance test system for the assembled reinforced retaining wall, an upper opening and a peripheral opening are formed in a test model box; the load loading device is used for applying load to the upper opening, and the load loading device is used for simulating the influence of the dead weight of the reinforced soil retaining wall, the external service environment, the load capacity of the vehicle, the vehicle speed, the running position and other factors on the structure of the reinforced soil retaining wall in actual application; and the opening part of the peripheral side is assembled into the reinforced retaining wall by using the prefabricated panel module, the actual condition of one side of the outdoor actual reinforced retaining wall damaged can be simulated, and the data acquisition equipment can convert the deformation quantity of the reinforced retaining wall after load, and convert the deformation quantity into data parameters which can be measured, so that the simulation data can be quantitatively managed. The reinforced retaining wall load performance test system is simple in structure, can effectively simulate the damage conditions of the reinforced retaining wall after the reinforced retaining wall is loaded, and enables the damage conditions to be digitalized and more intuitive. In addition, the method is convenient to operate, easy to simulate and measure, capable of effectively simplifying data of conventional simulation measurement, wide in applicability and capable of enabling measured data to be more appropriate to data of the actual reinforced retaining wall when damaged.
Drawings
The following detailed description of embodiments of the invention is provided in conjunction with the appended drawings, in which:
FIG. 1 is a front view of an embodiment of the present invention;
FIG. 2 is a top view of an embodiment of the present invention;
FIG. 3 is a functional block diagram of an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of an inverted trapezoidal internal layout of a reinforcement material in an embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a reinforcement reverse-wrapping type internal layout according to an embodiment of the present invention;
FIG. 6 is a schematic view of the structure of the rib material and the retaining wall panel in the embodiment of the present invention;
FIG. 7 is a particle size grading diagram of sand particles in accordance with an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or there can be intervening components, and when a component is referred to as being "disposed in the middle," it is not just disposed in the middle, so long as it is not disposed at both ends, but rather is within the scope of the middle. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
As shown in fig. 1 to 7, the invention provides an assembled reinforced retaining wall load performance test system, which comprises a test model box 1, a load loading device 3 and a data acquisition device 4, wherein the test model box 1 is provided with an upper side opening 11 and at least one peripheral side opening 12, a reinforced retaining wall 2 is arranged in the test model box 1, and the reinforced retaining wall 2 blocks the peripheral side opening 12; the load loading device 3 can apply vertical load to the reinforced retaining wall 2 in the test model box 1 from the upper opening 11 and measure the settlement of the reinforced retaining wall 2 in the vertical direction; the data acquisition equipment 4 is used for acquiring deformation of the reinforced retaining wall 2 after being loaded. The reinforced retaining wall load performance test system is characterized in that an upper opening 11 and a peripheral opening 12 are formed in a test model box 1; the load loading device 3 is used for applying load to the upper opening 11 and is used for simulating the influence of the self weight of the reinforced soil retaining wall 2, the external service environment, the load capacity of the vehicle, the vehicle speed, the running position and other factors on the structure in actual application; and the circumferential side openings 12 can simulate the actual situation of the damaged side of the outdoor actual reinforced retaining wall 2, and the data acquisition equipment 4 can convert the deformation quantity of the reinforced retaining wall 2 after being loaded into data parameters which can be measured, so as to quantitatively manage the simulation data. The reinforced retaining wall load performance test system is simple in structure, can effectively simulate the damage conditions of the reinforced retaining wall 2 after being loaded, and enables the damage conditions to be digitalized and more intuitive.
In the actual use, the reinforced earth retaining wall 2 of the simulation of this application test includes that the shutoff is fixed at the inside muscle material 22 of retaining wall panel 21 and the filler 23 of cladding outside muscle material 22 at the lateral opening 12 department's retaining wall panel 21, one end, muscle material 22 is provided with at least one deck, and this application is preferred more than five layers, improves measuring precision like this. The retaining wall panels 21 can be designed in a modularized manner, so that the actual structural process of the actual reinforced retaining wall 2 can be simulated, and in the embodiment, the retaining wall panels 21 can be made into regular square types, thereby facilitating the masonry work in the test process. Referring to fig. 6, in some embodiments, the retaining wall panel 21 may be directly prefabricated into a module, the retaining wall panel 21 is a hollow structural module, the reinforcing steel bars 24 are inserted into the hollow area, the retaining wall panel 21 has a groove at the upper portion, a protruding connecting member is provided at the lower portion, the protruding connecting member and the reinforcing steel bars 22 can be assembled to the circumferential side opening 12 together, and the connection between the reinforcing steel bars 22 and the retaining wall panel 21 can be a snap friction connection and a back-pack friction connection, and can also be a mechanical connection, depending on actual test conditions. The friction connection is mainly that the rib 22 is clamped between the modules of two adjacent retaining wall panels 21, the retaining wall panels 21 and the rib 22 are connected by using the friction force of the gap between the modules of the retaining wall panels 21, and the mechanical connection is that the reinforcing steel bar 24 in the retaining wall panels 21 directly penetrates through the rib 22 and realizes the limiting rib 22.
The rib 22 can be a biaxially oriented HDPE geogrid, the aperture specification of the biaxially oriented HDPE geogrid is 40mm × 40mm, and the strength model is TGSG-3030, wherein the biaxially oriented HDPE geogrid can be divided into an M type, an a type and a B type, the ultimate tensile strengths of the three types are about 32.7kN/M, 29.5kN/M and 16.7kN/M in sequence, and the peak failure strains are about 10.8%, 10.3% and 10.2% in sequence; the experimental M-shaped reinforcing material is obtained by processing the original bidirectional geogrid without shearing transverse ribs, 1 grid transverse rib is cut off when the A-shaped reinforcing material is 1 transverse rib at each interval, 2 grid transverse ribs are cut off when the B-shaped reinforcing material is 1 transverse rib at each interval, and the A-shaped reinforcing material and the B-shaped reinforcing material are obtained by processing on the basis of the M-shaped reinforcing material. The three types of bidirectional geogrids can effectively analyze the influence of the reduction of the strength of the grids on the working performance of the reinforced retaining wall. The following tests can be carried out according to the three types of geogrids, and the test accuracy is improved.
Referring to fig. 2 to 5, the data acquisition device 4 includes a flexible displacement meter 41, a displacement sensor 42, an accelerometer 43, and an earth pressure cell 44; wherein, the flexible displacement meter 41 is installed on the rib 22 and is used for measuring the deformation amount of the rib 22 after being loaded and the soil pressure cell 44; the displacement sensor 42 is installed on the peripheral side opening 12, and the displacement sensor 42 can slide relative to the retaining wall panel 21 and is used for measuring the horizontal displacement and the settlement in the vertical direction of the retaining wall panel 21 after being loaded; an accelerometer 43 mounted in the filler 23 for measuring the amount of acceleration after being subjected to a load at a place where it is buried; the soil pressure cell 44 is installed in the filler 23 and is used to measure the amount of soil pressure applied to the place where it is buried after a load is applied. It should be noted that the measurement value of the displacement sensor 42 is the deformation amount of the retaining wall panel 21 itself, and therefore it can be seen that the displacement sensor 42 needs to be fixed during the test. For this reason, in the present application test model box 1 is provided with mounting bracket 13 on the outside on one side of circumferential side opening 12, displacement sensor 42 is installed on mounting bracket 13, mounting bracket 13 does not contact with retaining wall panel 21, displacement sensor 42 abuts with retaining wall panel 21. In order to improve the accuracy of the test data during the test, the displacement sensor 42 is required to be coated with a lubricant in this application, so as to improve the sensitivity of the entire displacement sensor 42.
Referring to fig. 2, 4 and 5, the test model box 1 comprises a base 14 and a frame 15, wherein the frame 15 is mounted on the base 14, the frame 15 is provided with a rear steel plate 16 on one side opposite to the peripheral side opening 12, and the frame 15 is provided with a side steel plate 17 and a glass fiber reinforced plastic panel 18 on two sides of the peripheral side opening 12 respectively. The arrangement of the glass fiber reinforced plastic panel 18 is mainly convenient for a tester to observe the deformation condition of the inner reinforced retaining wall 2 of the whole test model box 1 in the test process. In another embodiment of the present application, the glass fiber reinforced plastic panel 18 is provided with corresponding scales, and the positions of the soil pressure boxes 44, the accelerometers 43, the reinforcements 22 and the fillers 23 for layered filling and compacting are marked according to the design requirements of the working conditions, so as to guide the smooth progress of the filling process. For the accuracy of the test, the test structure composed of the base 14, the frame 15, the rear steel plate 16, the glass fiber reinforced plastic panel 18 and the side steel plate 17 can be considered as non-deformable, so that the error caused by the deformation of the test model box 1 in the test process can be reduced, and the accuracy of the measured data is influenced.
In a modified embodiment, in order to better record the deformation condition of each soil layer, the testing system further comprises a digital image testing system 36, the digital image testing system 36 comprises a digital camera 34 and an image acquisition and analysis computer 35, the digital camera 34 and the image acquisition and analysis computer 35 are both arranged on one side of the glass fiber reinforced plastic panel 18, the digital camera 34 can acquire deformation displacement picture information of the filler 23 around different layers of the reinforcing materials 22, and the image acquisition and analysis computer 35 can receive the image information shot by the digital camera 34 and calculate and draw displacement clouds and strain fields of any layer of the filler 23 near the interface between the reinforcing materials 22 and the filler 23. The technology of acquiring an image by using a digital camera and analyzing image information by using a computer is a conventional technical means, and the applicant does not describe in detail the principle of how the computer analyzes the image information. In the test system, the digital camera 34 and the image acquisition and analysis computer 35 are connected to each other by a USB data cable. The digital image testing system 36 is arranged perpendicular to the glass fiber reinforced plastic panel 18 and opposite to the output end of the load loading device 3, and the distance is 500mm, so that the image obtained by the digital image testing system 36 is clear and has no distortion.
Referring to fig. 1 to 3, in order to improve the convenience of loading, the load loading device 3 of the present application includes a reaction frame 31, a hydraulic cylinder 32 having an output end downwardly disposed on the reaction frame 31, and a loading plate 33 disposed on an output end of the hydraulic cylinder 32, and the hydraulic cylinder 32 is capable of applying a vertical load to the reinforced retaining wall 2 in the test pattern box 1 through the loading plate 33. The loading plate 33 directly acts on the reinforced retaining wall 2, so that in order to avoid the influence of stress deformation of the loading plate 33, a steel plate with high rigidity is preferably selected as the loading plate 33 in the application, and the specification can be 95cm multiplied by 15cm multiplied by 3cm, thereby basically meeting the actual action area of the conventional load on the unit area of the reinforced retaining wall 2 in the actual process. In addition, how to control the action and the loading process of the hydraulic cylinder 32 can be preferably controlled by an MTS electro-hydraulic servo control system, the system can display the output load level value and the loading frequency in real time, and the load type can be converted by regulating and controlling the relevant parameters of the system. The specific structure and the use mode of the MTS electro-hydraulic servo control system can be seen as follows: the permission of green, ge yun hai, liu hong, & written, vegetarian, (0). application of MTS electro-hydraulic servo loading system to building structure tests.
Referring to fig. 3, in practical application, the load performance testing system for the fabricated reinforced retaining wall further comprises a data acquisition system, wherein the data acquisition system can receive data signals output by the flexible displacement meter 41, the displacement sensor 42, the accelerometer 43 and the soil pressure cell 44, and transmit the received data signals to an external upper computer. The data acquisition system preferably selects a static strain gauge and a dynamic strain gauge which are commonly used in the field, and the two different types of strain gauges can respectively measure deformation data of the reinforced retaining wall 2 in static and dynamic load states. The preferred type of the static strain gauge is JM 3813; and the preferred model of the dynamic strain gauge is JM3841 dynamic strain gauge. The data acquisition system can transmit the data to an upper computer after acquiring the data, so that an operator can observe and record the data in real time conveniently.
Referring to fig. 4 and 5, the present invention also provides a method for testing a load performance of an assembled reinforced retaining wall, comprising:
step 1, preparing test equipment, preparing a test model box 1, a load loading device 3 and data acquisition equipment 4, and debugging the load loading device 3 and the data acquisition equipment 4 until the preset requirements are met;
step 2, constructing a test unit layer, filling and compacting filler 23 and a rib 22 in the test model box 1 in a layered manner, installing a flexible displacement meter 41 on the rib 22, embedding an accelerometer 43 and a soil pressure cell 44 in the filler 23 according to preset positions, and building a retaining wall panel 21 consisting of assembly modules at the peripheral opening 12, so that the rib 22 is connected with the retaining wall panel 21 consisting of the assembly modules; a displacement sensor 42 capable of fixing the position relative to the test model box 1 is arranged on a retaining wall panel 21 formed by the assembled modules;
step 3, constructing a reinforced retaining wall 2, and filling test unit layers layer by layer according to the mode of the step 2 until a preset test height is reached and the reinforced retaining wall 2 is formed;
step 4, installing a loading plate 33, leveling the upper surface of the uppermost test unit layer of the reinforced retaining wall 2 by using a horizontal ruler after the reinforced retaining wall 2 is filled, and then placing the loading plate 33 on a preset pressure testing point of the uppermost test unit layer;
step 5, a loading test is carried out, the data acquisition equipment 4 is debugged, the test time of each measurement is unified, and the load loading device 3 carries out loading in a sine wave type loading mode until the reinforced retaining wall 2 is damaged; recording the various measurement data in the data acquisition device 4 during the test; the digital camera 34 acquires deformation displacement picture information of the filler 23 around different layers of the ribs 22, and the image acquisition and analysis computer 35 can receive the image information shot by the digital camera 34 and calculate and draw a displacement cloud picture and a strain field of the filler 23 layer near the interface of any layer of the ribs 22 and the filler 23; the applied sinusoidal excitation force is expressed as follows:
P＝P0+PAsin(2πft)
in the formula, P0Is the load constant (kN);
PAis the dynamic load amplitude (kN);
f is the loading frequency (Hz);
t is time(s);
and 6, ending the test, and shooting the accumulated deformation condition of the top loading plate 33 and the retaining wall panel 21 of the reinforced retaining wall and recording the number of cracks by using a high-definition digital camera after the reinforced retaining wall 2 is damaged.
In an actual test, factors such as the traffic load type, the driving speed, the load capacity, the road surface condition and the like in reality generate dynamic influence on the dynamic load level and frequency of the reinforced soil composite body under the traffic load, so that the traffic load is difficult to accurately simulate in reality; therefore, it is necessary to appropriately simplify the dynamic load waveform in the research, and the simplified waveform is in a sine wave form, so the load loading device 3 is loaded in a way of a sine exciting force expression, the whole simulation test is simplified, and the influence of the traffic load on the reinforced retaining wall 2 can be obtained more intuitively.
Referring to fig. 4 and 5, in the present application, the laying manner of the reinforcement 22 includes laying of an inverted trapezoid, a reverse-wrapped type and a bar-shaped grid, and performing model test analysis under two working conditions of dynamic static load and dynamic load respectively: applying vertical loads to the top of the reinforced retaining wall 2 in a grading manner until the top is damaged, respectively changing the offset distance D of the loading plate 33 to analyze the working performance of the reinforced retaining wall 2 by 5kN at each grade, wherein D is 0.3H, 0.45H and 0.6H, defining the ratio of the foundation offset distance D to the retaining wall height H as the strip foundation offset rate beta, preferably 1265mm, and determining the strip foundation optimal offset rate beta of the inner side of the layer panel of the foundation distance test unitopt. In order to study the working performance of the reinforced retaining wall 2 with different grid types, namely M, A, B type ribs and the length L of the ribs 22, the working performance of the reinforced retaining wall 2 with L being 1.0H, 0.7H and 0.4H is studied. The test conditions are detailed in table 1, the vertical soil pressure of the retaining wall vibration source position, the horizontal displacement at different heights h of the test unit layer panel and the strain of the rib material 22 are measured during the test, and the dynamic load effect effects of different conditions are contrastively analyzed. The experimental grouping scheme and parameters are detailed in Table 1, where f is frequency, P0For amplitude, N is the number of reinforcement layers, u is the distance between reinforcement layers, B is the base width, L is the length of the reinforcement material, and H is the height of the retaining wall.
TABLE 1 test grouping List
Figure RE-GDA0002941954940000131
Figure RE-GDA0002941954940000141
Wherein, the specific loading mode in the step 5 is as follows: the load loading device 3 firstly applies static load pressure step by step from zero to a preset dynamic load central value P0Each stage is loaded with nkN, n is a natural integer; then respectively and sequentially applying a dynamic load value P0±nkN、P0±2nkN、P0±3nkN、P0±4nkN、P0±5nkN、P0And 6 + 6nkN, wherein the loading time of each stage is 5-10min until the retaining wall is destroyed and the test is finished. Wherein a specific measurement value, i.e. P as described above, is given in the present application0When n is equal to 5 and 30, the load loading device 3 first applies static load pressurization step by step from zero to a preset dynamic load central value P0Each stage is loaded with 5kN at 30 kN; and then sequentially applying dynamic load values of 30 +/-5 kN, 30 +/-10 kN, 30 +/-15 kN, 30 +/-20 kN, 30 +/-25 kN and 30 +/-30 kN respectively, wherein the loading time of each stage is 5min until the retaining wall is destroyed and the test is finished.
In another embodiment of the present application, step 2 comprises the steps of:
step 2.1, filling and compacting filler 23 in a test model box 1 in a layered mode, and building retaining wall panels 21 formed by assembled modules at openings 12 on the peripheral sides, wherein the filling thickness of each test unit layer is 10-12 cm, and the height of the retaining wall is 110-144 cm; leveling and compacting the filler 23 for 3-5 times by using an electric flat plate compactor in the filling process, and compacting the filler 23 on a unit area by using a weight of 15-30 kg, wherein the compaction frequency per unit area is 4-7 times; gradually adding the filler 23 in the flattening process until the compaction thickness of the test unit layer is 12-16 cm, and the compaction coefficient is more than 95%;
step 2.2, paving a rib material 22 on the compacted test unit layer according to a preset specification, wherein one end of the rib material 22 is connected with a retaining wall panel 21 formed by an assembly type module; mounting a flexible displacement meter 41 on the rib material 22, and burying an accelerometer 43 and a soil pressure cell 44 in the test unit layer;
and 2.3, fixedly mounting a displacement sensor 42 on the mounting frame 13 outside the peripheral side opening 12, wherein the displacement sensor 42 is abutted against the outer side of the retaining wall panel 21 formed by the assembled module.
The purpose that sets up like this can effectively make the simulation reinforced earth barricade 2 of filling similar with 2 structures of actual reinforced earth barricade, has improved the accuracy of actual simulation test data. And the data acquisition equipment 4 is arranged in a layered design, so that the deformation condition of each layer of the whole reinforced retaining wall 2 after receiving the load can be effectively measured.
Of course, in the present application, in order to improve the accuracy of the test, the filler 23 in step 2.1 is medium sand with good grain composition, wherein the parameter of the medium sand selected in the present application is the non-uniformity coefficient Cu8.80 to 9.02, coefficient of curvature Cc1.30 to 1.35, an internal friction angle of 36 to 41 degrees, a cohesion c of 1.28 to 1.32kPa, and a dry density ρdmax1.68 to 1.78g/cm3. Wherein, the preferable basic parameters of sand obtained based on the indoor soil test in the embodiment are as follows: the density rho is 1.81g/cm3Specific gravity of the soil particles dsIs 2.65, dry density ρdIs 1.69g/cm3. The sand grain size grading curve is shown in figure 7.
The method is convenient to operate, easy to simulate and measure, capable of effectively simplifying data of conventional simulation measurement, wide in applicability and capable of enabling measured data to be more appropriate to data of actual reinforced retaining walls when damaged.
The above embodiments are only for illustrating the technical solutions of the present invention and are not limited thereto, and any modification or equivalent replacement without departing from the spirit and scope of the present invention should be covered within the technical solutions of the present invention.

Claims (10)

1. The utility model provides an assembled reinforced retaining wall load performance test system which characterized in that includes:
the test model box is provided with an upper side opening and at least one peripheral side opening, a reinforced retaining wall is arranged in the test model box, and the reinforced retaining wall is positioned at the peripheral side opening position;
the load loading device can apply vertical load to the reinforced retaining wall in the test model box from the upper opening and measure the settlement of the reinforced retaining wall in the vertical direction; and
and the data acquisition equipment is used for acquiring the deformation of the reinforced retaining wall after the reinforced retaining wall is loaded.
2. The system of claim 1, wherein the reinforced retaining wall comprises a retaining wall panel plugged at the opening of the peripheral side, a rib material with one end fixed at the inner side of the retaining wall panel, and a filler coated outside the rib material, and the rib material is provided with at least one layer.
3. The assembled reinforced retaining wall load performance test system of claim 2,
the data acquisition equipment comprises
The flexible displacement meter is arranged on the rib and used for measuring the deformation amount of the rib after the load is applied to the rib;
the displacement sensor is arranged on the opening on the peripheral side, can slide relative to the retaining wall panel and is used for measuring the horizontal displacement of the retaining wall panel after being loaded;
the accelerometer is arranged in the filler and is used for measuring the acceleration amount of the embedded part after being loaded;
and the soil pressure box is arranged in the filler and is used for measuring the soil pressure after the buried part is loaded.
4. The system of claim 3, wherein the test model box is provided with a mounting frame on the outer side of the opening on the circumferential side, the displacement sensor is mounted on the mounting frame, the mounting frame is not in contact with the retaining wall panel, and the displacement sensor is abutted against the retaining wall panel.
5. The system of claim 1, wherein the test model box comprises a base and a frame, the frame is mounted on the base, the frame is provided with a rear steel plate on the side opposite to the opening on the peripheral side, and the frame is provided with a side steel plate and a glass fiber reinforced plastic panel on the two sides of the opening on the peripheral side.
6. The assembled reinforced retaining wall load performance test system of claim 1, wherein the load loading device comprises a reaction frame, a hydraulic cylinder with an output end downwards arranged on the reaction frame, and a loading plate arranged on the output end of the hydraulic cylinder, and the hydraulic cylinder can apply vertical load to the reinforced retaining wall in the test model box through the loading plate.
7. The assembled reinforced retaining wall load performance test system of claim 2, further comprising a digital image test system, wherein the digital image test system comprises a digital camera and an image acquisition and analysis computer, and a transparent glass fiber reinforced plastic panel is arranged on one side of the test model box, which is provided with the opening on the peripheral side; the digital camera and the image acquisition and analysis computer are both arranged on one side of the glass fiber reinforced plastic panel, the digital camera can acquire deformation displacement picture information of the filler around different layers of the reinforced materials, and the image acquisition and analysis computer can receive image information shot by the digital camera and calculate and draw a displacement cloud picture and a strain field of the filler layer near the interface of any layer of the reinforced materials and the filler.
8. A load performance test method for an assembled reinforced retaining wall is characterized by comprising the following steps:
step 1, preparing test equipment, preparing a test model box, a load loading device and data acquisition equipment, and debugging the load loading device and the data acquisition equipment until the preset requirements are met;
step 2, constructing a test unit layer, filling and compacting filler and a rib material in a test model box layer by layer, mounting a flexible displacement meter on the rib material, embedding an accelerometer and a soil pressure cell in the filler according to a preset position, and building a retaining wall panel consisting of assembly modules at peripheral side openings so that the rib material is connected with the retaining wall panel consisting of the assembly modules; mounting a displacement sensor which can be fixed relative to the position of the test model box on a retaining wall panel formed by the assembly type module;
step 3, constructing a reinforced retaining wall, and filling test unit layers layer by layer according to the mode of the step 2 until a preset test height is reached and the reinforced retaining wall is formed;
step 4, mounting a loading plate, leveling the upper surface of the uppermost test unit layer of the reinforced retaining wall by using a horizontal ruler after the reinforced retaining wall is filled, and then placing the loading plate on a preset pressure testing point of the uppermost test unit layer;
step 5, a loading test is carried out, data acquisition equipment is debugged, the test time of each measurement is unified, and a load loading device carries out loading in a sine wave type loading mode until the reinforced retaining wall is damaged; recording each measurement data in the data acquisition equipment during the test; the digital camera obtains the deformation displacement picture information of the filler around different layers of the reinforced materials, the image acquisition and analysis computer can receive the image information shot by the digital camera and calculate and draw a displacement cloud picture and a strain field of the filler layer near the interface of any layer of the reinforced materials and the filler; the applied sinusoidal excitation force is expressed as follows:
P＝P0+PAsin(2πft)
in the formula, P0Is the load constant (kN); pAIs the dynamic load amplitude (kN); f is the loading frequency (Hz); t is time(s);
and 6, ending the test, and shooting the accumulated deformation conditions of the top layer loading plate and the retaining wall panel of the reinforced retaining wall and recording the number of cracks by using a high-definition digital camera after the reinforced retaining wall is damaged.
9. The method for testing the load performance of the assembled reinforced retaining wall according to claim 8, wherein the specific loading manner in the step 5 is as follows: the load loading device firstly applies static load to pressurize to a preset dynamic load central value P step by step from zero0Load per stagenkN, n is a natural integer; then respectively and sequentially applying a dynamic load value P0±nkN、P0±2nkN、P0±3nkN、P0±4nkN、P0±5nkN、P0And 6 + 6nkN, wherein the loading time of each stage is 5-10min until the retaining wall is destroyed and the test is finished.
10. The method for testing the load performance of the fabricated reinforced retaining wall according to claim 8, wherein the step 2 comprises the following steps:
step 2.1, filling and compacting fillers in a test model box in a layered mode, and building retaining wall panels formed by assembled modules at openings on the peripheral sides, wherein the filling thickness of each test unit layer is 10-12 cm, and the height of the retaining wall is 110-144 cm; in the filling process, an electric flat plate compactor is adopted to level and compact the filler for 3-5 times, and then a weight of 15-30 kg is used to compact the filler on a unit area, wherein the compaction frequency per unit area is 4-7 times; gradually adding the filler in the flattening process until the compaction thickness of the test unit layer is 12-16 cm, and the compaction coefficient is more than 95%;
step 2.2, paving a rib material on the compacted test unit layer according to a preset specification, wherein one end of the rib material is connected with a retaining wall panel formed by the assembly type module; mounting a flexible displacement meter on the rib, and embedding an accelerometer and a soil pressure cell in the test unit layer;
and 2.3, fixedly mounting a displacement sensor on the mounting frame outside the opening on the peripheral side, wherein the displacement sensor is abutted against the outer side of the retaining wall panel formed by the assembled module.
CN202011516456.5A 2020-12-21 2020-12-21 System and method for testing load performance of assembled reinforced retaining wall Pending CN112649304A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113887091A (en) * 2021-08-09 2022-01-04 青岛理工大学 Assembly type building simulation test system and method
CN114002060A (en) * 2021-09-27 2022-02-01 西南交通大学 Performance test system and method of reinforced geotechnical structure under multi-field coupling effect

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113887091A (en) * 2021-08-09 2022-01-04 青岛理工大学 Assembly type building simulation test system and method
CN114002060A (en) * 2021-09-27 2022-02-01 西南交通大学 Performance test system and method of reinforced geotechnical structure under multi-field coupling effect

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