CN114199186A - Excavation-controllable foundation pit model test device and method - Google Patents
Excavation-controllable foundation pit model test device and method Download PDFInfo
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- CN114199186A CN114199186A CN202111434519.7A CN202111434519A CN114199186A CN 114199186 A CN114199186 A CN 114199186A CN 202111434519 A CN202111434519 A CN 202111434519A CN 114199186 A CN114199186 A CN 114199186A
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C5/00—Measuring height; Measuring distances transverse to line of sight; Levelling between separated points; Surveyors' levels
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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
- G01B5/02—Measuring arrangements characterised by the use of mechanical techniques for measuring length, width or thickness
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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
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L11/00—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00
Abstract
The invention relates to a foundation pit model test device with controllable excavation, which comprises a model box outer frame, simulation soil, a supporting baffle plate component, a supporting component and a test instrument component, wherein the model box outer frame is provided with a plurality of supporting baffle plates; the outer frame of the model box consists of a front upright post, an enclosure baffle, an organic glass side plate, a back plate and a front pull rod; the supporting baffle plate component mainly comprises a supporting baffle plate, a supporting baffle plate reinforcing rib and a supporting baffle plate upright post; the supporting component mainly comprises a rotating handle, a screw rod, a spring inner sleeve, a spring outer sleeve and a supporting component connecting end plate; the testing instrument component comprises a top settlement reference rod, a top settlement dial indicator, a micro soil pressure gauge, a micro pore water pressure gauge, a signal acquisition instrument and a computer. The invention has the beneficial effects that: the model device is provided with the supporting component between the retaining baffle and the supporting baffle, and can realize foundation pit excavation through unloading of the supporting component, thereby facilitating simulation of foundation pit excavation and avoiding artificial disturbance during manual excavation.
Description
Technical Field
The invention belongs to the field of foundation pit engineering, and particularly relates to a foundation pit model test device and method with controllable excavation.
Background
Limited by site environment and construction conditions, many students study the deformation and internal force of the enclosure structure, the surrounding strata and the adjacent building structures in the excavation process of foundation pits in different forms through model tests. The model test of foundation pit excavation comprises two steps, namely excavation of soil in the pit and support erection of the enclosure structure, and the two steps have great influence on the result of the model test. The excavation of the foundation pit is usually carried out in a layered and partitioned mode, the nonlinearity of the mechanical property of the soil body and the excavation of the soil body are usually carried out manually by using a shovel, and the two factors cause that the excavation of each soil body in the model test is not controllable, such as the control of the excavation amount of each soil body and the control of the excavation time of each soil body, and the disturbance of soil shoveling operation on the peripheral soil body and the enclosure structure in the excavation of each soil body. The support erection of the enclosure structure is also a difficult point in a model test, the support rod is jacked on the enclosure structure through manpower during support erection, the enclosure structure is disturbed, the support rod has certain prestress on the enclosure structure after erection, and the traditional model test is lack of prestress control measures.
The existing in-situ testing technology can accurately test the internal force and deformation conditions of the enclosure structure and the surrounding environment during excavation of the foundation pit. Only many new processes need model test demonstration before being implemented on the actual site, and therefore, comparison research needs to be carried out through model tests. In model experiments, the effect of a certain process needs to be researched through comparison experiments, and interference of other non-process factors needs to be eliminated. For example, two comparative runs are required to investigate the effect of a process, one using the process and the other not. The non-technological factors are ensured to be the same in the implementation process of the two sets of tests, and the non-technological factors comprise the supporting shaft force of the pre-jacking after the foundation pit is excavated, the manual interference during excavation in the pit, the mutual influence of soil bodies in the pit during excavation, the strength of the soil bodies in the pit and the like. Therefore, in order to ensure the validity of the model test result, it is necessary to design a new model test box which can realize the control of the support pre-applied axial force without manual interference during the excavation of the foundation pit.
The deformation measurement of the building envelope in the model test is also a difficult point, and some scholars paste strain gauges on the building envelope and obtain the deformation of the building envelope through strain conversion, but the test method is limited by temperature and the number of test points, so that the actual deformation of the building envelope is difficult to accurately measure. Some students install a dial indicator on the enclosure structure, and although the dial indicator can accurately measure the deformation of the enclosure structure, the dial indicator needs to be connected with a gauge stand by a connecting rod and is limited by the size of a model box, and only displacement monitoring can be carried out on individual parts of the enclosure structure during actual test.
The related patent documents are as follows:
the foundation pit model test device capable of simulating underground water level change in the foundation pit excavation process has application number 201610205963.4, and comprises a model box, a water tank, a symmetrical surface soil retaining unit and a foundation pit supporting structure; the model box consists of a model box frame, toughened glass, a model box bottom plate, a counter-force plate, a top frame and a model box base; the water tank is arranged at the upper right part in the model box and is used for controlling and observing water level change in soil; the symmetrical surface soil retaining units are U-shaped stainless steel bars, are used for temporarily retaining the unearthed soil body on the driven side of the foundation pit and are fixed on the model box frame through bolts; the foundation pit supporting structure comprises a retaining wall and a support. The invention can simulate each construction condition of the foundation pit excavation project under the dynamic change of the underground water level, and ensures the accuracy of the simulation test.
The utility model provides an adjustable waterproof excavation supporting device based on excavation model test of foundation ditch's application number 201610204554.2, the device includes retaining wall and support. A plurality of bolts are arranged at the upper part of the retaining wall, and the retaining wall bracket is fixed through the bolts; a plurality of fixing bolts are reserved in the middle of the retaining wall, and water stop rubber strips are arranged on two sides of the retaining wall; the water stop rubber strips ensure that no water leakage occurs on the contact surface of the retaining wall and the model box in the moving process; one end of the support is provided with an internal thread port, and the internal thread port is in threaded connection with the fixing bolt, so that the support is installed. The device is rational in infrastructure, and installation convenient operation can be used to displacement and the deformation of flexible retaining wall in the foundation ditch excavation model test under the simulation groundwater environment.
The patent is 'model box and test method for foundation pit excavation model test' with application number 202010820261.3, and is characterized in that a cavity with an upward opening is formed in a box body; the two enclosure structures are vertically arranged in the cavity and divide the cavity into three accommodating cavities; the supporting structure is connected between the two building enclosures; and filling soil bodies with the same or different heights in the containing cavities on the two sides of the two building envelopes to perform model tests of equal pressure or bias pressure on the two sides of the foundation pit. Meanwhile, a foundation pit excavation model test method is also provided.
The patent of ' foundation pit excavation model test device based on surface water penetration ' and using method ' with application number 201910213283.0 includes a model box, an artificial lake design water tank, a foundation pit supporting structure, an angle steel frame and a measuring system; the model box is a transparent square box body, so that the permeation condition of surface water to the foundation pit enclosure wall in the test, the displacement of the foundation pit supporting structure and the deformation of a soil body can be observed conveniently; the artificial lake is designed with a water tank for simulating the permeation of the artificial lake; the foundation pit supporting structure is fixedly connected with the model box through an angle steel frame, and a monitoring instrument is arranged on the foundation pit supporting structure and connected with a measuring system; and simulating the response condition of excavation deformation of the foundation pit under the surface water seepage effect, and observing and researching the seepage influence range of the surface water on the foundation pit surrounding wall and the influence on the excavation deformation of the supporting structure.
The patent relates to a model test device for the influence of double diaphragm wall foundation pit excavation on the convergence deformation of a tunnel, which has the application number of 201610259592.8, wherein the top surface of a model box is provided with an opening, and a tunnel lining model is placed in a soil body in the model box and is parallel to the short edge of the model box; the underground continuous wall model is placed on the right side of the model box; the transverse supporting model is fixed inside the underground diaphragm wall model; the foundation pit bottom plate model is fixed at the bottom of the foundation pit; the infrared distance measuring devices are fixed on the inner wall of the tunnel lining model, and a pair of infrared distance measuring devices are arranged in pairs; the measuring point is pre-embedded into the tunnel lining model through a wire and connected to the infrared ranging output system for real-time derivation of the accurate convergence deformation condition of the measuring point.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a foundation pit model test device and method with controllable excavation, which can conveniently measure the deformation of a building enclosure, avoid the interference caused by manual excavation during foundation pit excavation, and pre-add the set supporting axial force according to the requirement.
The foundation pit model test device with controllable excavation comprises a model box outer frame, simulation soil, a supporting baffle plate component, a supporting component and a test instrument component.
The outer framework of the model box consists of a base, a front upright post, a rear upright post, an enclosure baffle, an organic glass side plate, a back plate, a side plate reinforcing rib, a back plate reinforcing rib and a front pull rod. The base is formed by welding and splicing a plurality of steel plates and a plurality of I-shaped steel. The front upright post is provided with a retaining baffle and an insertion groove of an organic glass side plate. Holes are distributed on the front upright posts and correspond to the holes on the edges of the two sides of the enclosure baffle, and the front upright posts and the enclosure baffle are fixed through screws. The back upright post is provided with a back plate and an inserting groove of an organic glass side plate. The enclosure baffle is made of an organic glass plate, and a drill hole is formed in the enclosure baffle. And a supporting component steel base plate is arranged between the supporting component and the enclosure baffle, and the supporting component steel base plate is connected with the enclosure baffle through a screw. The back plate is arranged between the two rear upright posts and is positioned at the rear part of the model box. The side plate reinforcing ribs are welded between the front upright post and the rear upright post. The back plate is provided with back plate reinforcing ribs. The front pull rod is arranged between the two front upright posts.
The simulated soil consists of gypsum, fly ash, sand, barite powder and water.
The supporting baffle plate component mainly comprises a supporting baffle plate, a supporting baffle plate reinforcing rib and a supporting baffle plate upright post. The supporting baffle both sides are fixed through the supporting baffle stand, and the supporting baffle stand is equipped with the slot that is used for fixed stay baffle, sets up supporting baffle on the supporting baffle and strengthens the rib, sets up supporting baffle lateral part connecting rod between supporting baffle stand and the preceding stand.
The support component mainly comprises a rotating handle, a screw rod, a support baffle screw rod fixing piece, a sliding outer sleeve, a sliding inner sleeve, a spring inner sleeve, a displacement measuring plate, a spring outer sleeve, a limiting pin, a dial indicator connecting piece and a support component connecting end plate. The spring inner sleeve is arranged in the spring outer sleeve, a groove is formed in the side portion of the spring outer sleeve, a hole is formed in the end portion of the spring inner sleeve, and the limiting pin penetrates through the groove and the hole. The spring is arranged in the spring inner sleeve. The outer end of the outer spring sleeve is provided with a supporting part connecting end plate, and the outer end of the inner spring sleeve is provided with an iron plate. The spring outer sleeve is provided with a dial indicator connecting piece, and the dial indicator is arranged on the dial indicator connecting piece through a screw. The exposed section of the spring inner sleeve is provided with a displacement measuring plate, and a measuring head of the dial indicator props against the displacement measuring plate. One end of the screw rod is propped against the outer end of the spring inner sleeve, and the other end of the screw rod is provided with a rotating handle. The support baffle is provided with a support baffle screw rod fixing part, the inner side of the support baffle is provided with a sliding outer sleeve, the sliding inner sleeve is arranged in the sliding outer sleeve, and the sliding inner sleeve is welded at the outer end of the spring inner sleeve. The screw rod is arranged in the screw rod fixing part of the supporting baffle and penetrates through the sliding outer sleeve and the sliding inner sleeve on the inner side of the supporting baffle. The support component connecting end plate is connected with the enclosure baffle plate and the support component steel backing plate through screws.
The testing instrument component comprises a top settlement reference rod, a top settlement dial indicator, a micro soil pressure gauge, a micro pore water pressure gauge, a signal acquisition instrument and a computer. The top settlement dial indicator is placed on the top settlement reference rod through the gauge stand, and the top settlement reference rod is fixed above the outer frame of the model box through the top settlement reference rod support. A micro soil pressure gauge and a micro pore water pressure gauge are arranged in the simulated soil. The miniature soil pressure gauge and the sensor lead of the miniature pore water pressure gauge are connected with a signal acquisition instrument, and the signal acquisition instrument is connected with a computer.
Preferably, the method comprises the following steps: the mass ratio of sand, gypsum, water, fly ash and barite powder of the simulated soil is 200: 6: 130: 80: 60.
preferably, the method comprises the following steps: the measuring range of the dial indicator is 50mm, and the measuring precision is 0.01 mm.
Preferably, the method comprises the following steps: the miniature soil pressure gauge has the advantages of 1000kPa measuring range, 16mm diameter, 4.8mm thickness, sensitivity coefficient of about 2mv/MPa, precision of less than or equal to 0.5 percent F.S and full-scale output (mu epsilon): about 2000, bridging mode: full bridge, bridge resistance (Ω): 350.
preferably, the method comprises the following steps: the micro pore water pressure gauge has the measuring range of 500Pa, the diameter of 15.8mm, the height of 21mm, the resolution of 0.05KPa, the sensitivity coefficient of about 0.02mv/KPa and the precision of less than or equal to 0.3 percent F.S. The bridging mode is as follows: full bridge, bridge resistance (k Ω): 10.
The assembling and testing method of the excavation-controllable foundation pit model testing device comprises the following steps:
and S1, finishing the construction of the base by using an iron plate and I-shaped steel. And welding a supporting baffle upright post, a front upright post and a rear upright post on the base. Weld up the curb plate between front column and the back stand and strengthen the rib, and insert the organic glass curb plate. And a front pull rod support is welded on the top of the front upright post, and two ends of the front pull rod are inserted into the slots of the front pull rod support. And a back plate is inserted between the two rear upright columns, and back plate reinforcing ribs are welded. Inserting the supporting baffle in the slot of the supporting baffle upright column, and welding the reinforcing rib of the supporting baffle. Inserting a guard baffle in the slot of the front upright post, installing a support component steel backing plate on the guard baffle, installing a support component between the guard baffle and the support baffle, and installing a support baffle lateral connecting rod between the support baffle upright post and the front upright post. And (3) a waterproof membrane is filled in the model box, a top settlement reference rod support is welded above the model box, then the top settlement reference rod is installed, and the top settlement dial indicator is installed on the top settlement reference rod through a gauge stand, so that the assembling work of the model box is completed.
S2, before the model test is started, the enclosure baffle is stably installed, waterproof treatment is performed on the two ends and the bottom of the enclosure baffle, the screw rod of the supporting component is gradually pushed forward by rotating the handle, and when the dial indicator of the supporting component has digital change, the supporting component and the enclosure baffle are mutually pushed. The dial indicator data on all support members is recorded and this is indicated with B1. Filling simulated soil into the model box, burying the miniature soil manometer and the miniature pore water manometer according to the test requirements in the soil filling process, leading out a sensor lead from the side part of the model box to be connected with a signal acquisition instrument, and connecting the signal acquisition instrument with a computer. After filling, the containment baffle is deformed under the action of soil pressure to push the supporting component, at the moment, dial indicator data on the supporting component are changed, the dial indicator data at the moment are recorded, the dial indicator data are represented by B2, the elastic coefficient of the supporting component is k, supporting axial force F generated by the existing supporting component under the action of soil mass load outside the pit is k (B2-B1), the supporting axial force at the moment is balanced with the soil pressure outside the pit, and if foundation pit excavation is simulated, the supporting component on a certain layer is loosened.
S3, after the foundation pit is excavated, the deformation of the enclosure baffle is known, and the deformation measurement of the enclosure baffle is divided into three conditions: the first is that the deformation of the excavated surface is measured after the screw rod of the supporting component is loosened; the second method is that the supporting part is not loosened and the deformation below the excavation surface is measured; the third is the deformation measurement when the screw of the support member is loosened and then retightened.
S4, when the erection of the support is to be simulated, the screw rod of a certain support is screwed through the rotary handle, the dial indicator is observed when the rotary handle rotates, the reading at the moment is recorded when the data of the dial indicator starts to change, the data of the dial indicator is still represented by B1, B2 is inversely calculated according to the supporting axial force calculation formula F ═ k | (B2-B1) |, from the preset supporting axial force F, and the screw rod is stopped being screwed when the numerical value of the dial indicator reaches B2, so that the erection of the support is completed.
And S5, observing the reading of a dial indicator of the supporting component to know the influence of the additional load outside the foundation pit on the deformation and the axial force during the foundation pit model test, wherein the variation of the reading of the dial indicator is the deformation of the enclosure baffle, and the variation of the axial force of the supporting component is obtained according to a calculation formula F ═ k | (B2-B1) |.
Preferably, the method comprises the following steps: in step S1, the material and thickness of the enclosure baffle are preferably calculated by the similarity ratio theory based on the working condition to be simulated.
Preferably, the method comprises the following steps: in step S1, the side connecting rods of the supporting baffle are preferably screwed together, so that the side connecting rods are easy to disassemble and assemble during the test, and the side connecting rods are easy to debug and install the supporting component after being disassembled.
Preferably, the method comprises the following steps: in step S1, each support member should be calibrated on a compression tester, the relationship between the pressure and the compression deformation of each support member is determined, and each support member is numbered.
Preferably, the method comprises the following steps: in step S1, the spring length of each support member is preferably such that the spring is mounted in the support with a slight pre-stress.
Preferably, the method comprises the following steps: in step S2, according to the similarity ratio theory of the model test, the prepared soil for the model test is suitable for adjusting the mixture ratio according to the soil type to be simulated in the test. Before the model test, the orthogonal test is carried out on the soil samples with different proportions, the influence curve of various raw materials on the strength of the soil sample is drawn, and the proportion which is closest to the soil body to be simulated is found.
Preferably, the method comprises the following steps: in step S2, if the initial soil pressure and the pore water pressure after the completion of the simulated soil filling need to be tested, the micro soil pressure gauge and the micro pore water pressure gauge need to be connected to a computer and data acquisition is started before the soil filling.
Preferably, the method comprises the following steps: in step S3, in the first case, the deformation of the enclosure baffle is measured, and a vernier caliper is used to measure the distance between the exposed end of the screw rod and the support baffle, that is, the jacking distance of the screw rod is known by measuring the screwing thread of the screw rod. The exposed length of the lead screw before loosening is set as S1, the reading variation of a dial indicator of the support part before loosening is set as B2-B1, the lead screw is screwed again when the deformation of the enclosure baffle at the moment is measured, the lead screw is stopped when the reading of the dial indicator changes, the exposed length of the lead screw at the moment is recorded as S2, the moving distance of the lead screw is S2-S1, the deformation of the enclosure baffle is obtained by subtracting the deformation of the enclosure baffle by a thread B2-B1 for unloading the spring, and the deformation calculation formula of the enclosure baffle in the first case is (S2-S1) - (B2-B1).
And (3) measuring the deformation of the enclosure baffle in the second case, directly reading the data on the excavated dial indicator, and recording the data as B3, wherein the deformation calculation formula of the enclosure baffle in the second case is B3-B2.
The deformation measurement of the enclosure baffle in the third case is based on the first case, namely the measurement in the third case is carried out after the measurement in the first case is finished. When the screw rod is screwed again, the exposed length of the screw rod at the moment is recorded as S3, the reading of the dial indicator is B4, and the deformation amount of the enclosure baffle in the third case is (S3-S2) - (B4-B3) compared with that in the first case. And adding the deformation amount of the enclosure baffle in the first case, wherein the deformation amount of the enclosure baffle in the third case is S3-S1-B4-B2+ B3+ B1.
The invention has the beneficial effects that:
1. the model device is provided with the supporting component between the retaining baffle and the supporting baffle, and can realize foundation pit excavation through unloading of the supporting component, thereby facilitating simulation of foundation pit excavation and avoiding artificial disturbance during manual excavation.
2. The support component of the model device is provided with the screw rod, the screw rod is screwed up through the rotating handle to realize support erection, the simulation of support erection is facilitated, and artificial disturbance during manual erection of the support is avoided.
3. This model device can screw up the lead screw through rotatory handle and realize supporting the application of adding the axial force in advance, and the numerical value through observing the percentage table realizes adding the accurate of axial force in advance and applys.
4. The model device can realize displacement measurement of the enclosure structure by measuring the telescopic quantity of the screw rod, and is simple to operate.
5. The supporting part of the model device is provided with the dial indicator, and the influence of the external force outside the pit on the supporting axial force can be mastered by observing the data of the dial indicator on the supporting part.
Drawings
FIG. 1 is a schematic diagram of a front structure of a model test chamber;
FIG. 2 is a schematic diagram of a rear structure of a model test chamber;
FIG. 3 is a schematic illustration of support member assembly;
FIG. 4 is a top plan view of the model test chamber;
FIG. 5 is a schematic view of a containment barrier drilling;
FIG. 6 is a schematic view of a connecting hole between the enclosure baffle and the steel backing plate of the support member;
FIG. 7 is a schematic view of a connecting hole between the enclosure baffle and the support member;
FIG. 8 is a schematic view of a support member pad drilling;
FIG. 9 is a schematic cross-sectional view of a front pillar;
FIG. 10 is a schematic cross-sectional view of a rear pillar;
FIG. 11 is a schematic cross-sectional view of a support baffle column;
FIG. 12 is a schematic view of a dial indicator connection;
FIG. 13 is a schematic view of a spring outer sleeve;
FIG. 14 is a schematic view of the inner sleeve of the spring;
FIG. 15 is a schematic view of the sliding outer cylinder;
FIG. 16 is a schematic view of a glide sleeve;
FIG. 17 is a schematic view of the support member connecting the end plates;
FIG. 18 is a schematic cross-sectional view of a top settlement reference bar support;
FIG. 19 is a schematic cross-sectional view of a top settlement reference bar;
FIG. 20 is a cross-sectional view of a stiffening rib.
Description of reference numerals: 1-base, 2-enclosure baffle, 3-support part steel backing plate, 4-support baffle, 5-support baffle reinforcing rib, 6-support baffle column, 7-support part, 8-support baffle lateral connecting rod, 9-front column, 10-rear column, 11-organic glass lateral plate, 12-back plate, 13-lateral plate reinforcing rib, 14-back plate reinforcing rib, 15-simulated soil, 16-miniature soil pressure gauge, 17-miniature pore water pressure gauge, 18-sensor lead, 19-signal acquisition instrument, 20-computer, 21-top settlement percentage table, 22-top settlement reference rod, 23-top settlement reference rod support, 24-front pull rod, 25-front pull rod support, 26-a rotating handle, 27-a screw rod, 28-a support baffle screw rod fixing piece, 29-a sliding outer sleeve, 30-a sliding inner sleeve, 31-a spring inner sleeve, 32-a displacement measuring plate, 33-a spring outer sleeve, 34-a limit pin, 35-a dial indicator, 36-a dial indicator connecting piece, 37-a support component connecting end plate, 38-a spring, 39-a model box outer frame, 40-a support baffle component and 41-an elastic pressure rod.
Detailed Description
The present invention will be further described with reference to the following examples. The following examples are set forth merely to aid in the understanding of the invention. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.
Example one
The embodiment of the application provides a controllable foundation ditch model test device excavates, including model case outer frame 39, simulation soil 15, support baffle part 40, support component 7 and test instrument subassembly.
The outer framework 39 of the model box consists of a base 1, a front upright post 9, a rear upright post 10, an enclosure baffle 2, an organic glass side plate 11, a back plate 12, a side plate reinforcing rib 13, a back plate reinforcing rib 14 and a front pull rod 24. The base 1 is formed by welding and splicing 4 steel plates with the size of 2m multiplied by 1.25m and 11I-shaped steel with the height of 10 cm. The base 1 is used as a platform for model test, and the stability of each part of the model test is ensured. The front upright column 9 is used for connecting the enclosure baffle 2 and the organic glass side plate 11, so the front upright column 9 comprises slots of the enclosure baffle 2 and the organic glass side plate 11, the front upright column is 1.1m high, and the section is shown in the attached drawing 9. In addition, in order to prevent the enclosure baffle 2 from being separated from the slot of the front upright post 9 due to excessive deformation, a certain number of holes are distributed on the front upright post 9 and are consistent with the holes at the edges of the two sides of the enclosure baffle 2, so that the front upright post 9 and the enclosure baffle 2 can be mutually fixed through screws. The rear pillar 10 is for connecting the back plate 12 and the organic glass side plate 11, and therefore the rear pillar 10 includes slots for the back plate 12 and the organic glass side plate 11. The height of the rear upright post is 1.1m, and the section is shown in figure 10. The enclosure baffle 2 is used for simulating an enclosure structure during foundation pit excavation, the enclosure baffle is made of an organic glass plate, the thickness of the organic glass plate is 8mm, and the positions of the organic glass plate and a drilling hole are shown in an attached drawing 5. In order to facilitate the connection with the supporting component through the screw, holes are drilled in the enclosing baffle, as shown in figure 7. Meanwhile, in order to prevent the support part from directly abutting against the enclosure baffle to cause the damage of the enclosure baffle, a steel base plate is arranged between the support part and the enclosure baffle, the steel base plate is connected with the enclosure baffle through screws, and the positions of the connecting holes are shown in the attached drawings 6 and 8. The organic glass side plate 11 is 2cm in thickness, 1.5m in length and 1.1m in height. This size can ensure that the side direction soil pressure when the model test can not cause organic glass curb plate 11 to warp, and transparent organic glass curb plate 11 is convenient for observe the deformation condition of the interior soil body of model case in addition. The back plate 12 is located at the rear of the mold box, and the back plate 12 is made of an iron plate having a thickness of 6 mm. The side plate reinforcing ribs 13 are welded between the front upright post 9 and the rear upright post 10, so that the lateral deformation resistance of the organic glass side plate 11 can be enhanced, and the front and rear side upright posts can be prevented from being bent due to soil pressure. The back plate reinforcing ribs 14 not only can enhance the lateral deformation resistance of the back plate 12, but also can prevent the rear upright post 10 from bending due to soil pressure. The front tie rod 24 is used to improve the bending resistance of the two front uprights 9.
The simulated soil 15 is used for simulating saturated soft soil, and the simulated soil 15 is formed by mixing five materials of gypsum, fly ash, sand, barite powder and water. Wherein the sand is used as main aggregate, the gypsum is used for adjusting cohesive force of the simulated soil 15, the fly ash is used for filling gaps of the aggregate, the barite powder is used for adjusting specific gravity of the simulated soil 15, and the water is used for saturating the simulated soil 15. Compared with actual soft soil, the simulated soil 15 has good water permeability, fast saturation and fast water loss, can prepare soil with various required characteristics according to the adjustment of water content, and can save the time of model test by easily turning over the shovel.
The supporting baffle plate component 40 is composed of a supporting baffle plate 4, a supporting baffle plate reinforcing rib 5 and a supporting baffle plate upright post 6. The supporting baffle 4 is an iron plate with the thickness of 6mm and the thickness of 2m multiplied by 1.1 m. The support baffle reinforcing ribs 5 are square steel with the length of 2m, and the support baffle reinforcing ribs 5 are used for increasing the deformation resistance of the support baffle 4. The upright column 6 of the supporting baffle is used for fixing the supporting baffle, the upright column is provided with a slot for fixing the supporting baffle, and the section of the upright column 6 of the supporting baffle is shown in figure 11.
The supporting component 7 is composed of a rotating handle 26, a screw rod 27, a supporting baffle screw rod fixing piece 28, a sliding outer sleeve 29, a sliding inner sleeve 30, a spring inner sleeve 31, a displacement measuring plate 32, a spring outer sleeve 33, a limiting tip 34, a dial indicator 35, a dial indicator connecting piece 36 and a supporting component connecting end plate 37, as shown in figure 3. The elastic strut 41 is made by taking advantage of this characteristic of the spring 38, taking into account that the deformation of the spring 38 is linearly related to the force. Since the length of the inner spring sleeve 31 exceeds the drilling distance of the lathe, two sleeves need to be processed and then connected through threads, so that the inner spring sleeve 31 is manufactured. A slot is cut into the side of the outer spring sleeve 33 and a hole is drilled into the end of the inner spring sleeve 31 for receiving a stop pin 34. The spring 38 is plugged into the inner spring sleeve 31, the inner spring sleeve 31 is plugged into the outer spring sleeve 33, the limit pin 34 is mounted on the inner spring sleeve 31 after plugging, one end of the inner spring sleeve 31 is clamped in the outer spring sleeve 33, the end part of the outer spring sleeve 33 is welded with the support part connecting end plate 37, and the other end of the inner spring sleeve 31 is welded with an iron plate, so that the elastic pressing rod 41 is manufactured. To release the pressure of the elastic strut 41, the amount of compression of the elastic strut 41 needs to be measured. The dial indicator connector 36 is welded to the spring outer sleeve 33, and the dial indicator 35 is mounted on the dial indicator connector 36 by screws. The displacement measuring plate 32 is welded on the exposed section of the spring inner sleeve 31, and the measuring head of the dial indicator 35 can be used for measuring the compression amount of the elastic pressure rod 41 by propping against the displacement measuring plate 32. In order to accurately control the compression amount of the elastic pressure rod 41, one end of the screw rod 27 is pressed against the elastic pressure rod 41, the screw rod 27 is pushed in by rotating the screw rod 27, a support baffle screw rod fixing piece 28 is arranged on the support baffle 4 in order to realize the pushing function of the screw rod 27, a sliding outer sleeve 29 is arranged on the inner side of the support baffle 4, and the sliding inner sleeve 30 is welded on the elastic pressure rod 41. The screw rod 27 is arranged in the screw rod fixing piece 28 of the support baffle, penetrates out of the sliding outer sleeve 29 on the inner side of the support baffle 4 and is plugged into the sliding inner sleeve 30. The support component connecting end plate 37 is connected with the enclosure baffle 2 and the support component steel backing plate 3 through screws. At this point, the mounting of the support member is completed. The support is erected and the foundation pit is excavated by screwing or unscrewing the screw rod. The screw rod is combined with the support baffle screw rod fixing piece, the sliding outer sleeve and the sliding inner sleeve to realize the function of applying axial force or excavating and unloading by jacking and supporting the screw rod. The supporting shaft force and the displacement of the enclosure baffle can be calculated by measuring the jacking amount of the screw rod and the compression amount of the spring. The compression amount of the spring is mastered by measuring the displacement of the displacement measuring plate through the dial indicator. The supporting shaft force is further grasped by the compression amount of the spring.
The testing instrument mainly comprises a top settlement reference rod 22, a top settlement dial indicator 21 (containing a gauge stand), a micro soil pressure gauge 16, a micro pore water pressure gauge 17, a signal acquisition instrument 19 and a computer 20. The top settlement dial gauge 21 is placed on the top settlement reference bar 22 through a gauge stand to measure the top surface settlement of the simulated soil 15. The miniature soil pressure gauge 16 is used for testing the soil pressure change of the simulated soil 15 at different positions. The micro pore water pressure gauge 17 is used for testing the pore water pressure change of the simulated soil 15 at different positions. The sensor leads 18 of the micro soil pressure gauge 16 and the micro pore water pressure gauge 17 are connected to a signal acquisition instrument 19, and the signal acquisition instrument 19 is connected to a computer 20. Thus, the test instrument is prepared.
Example two
The second embodiment of the application provides an assembling and testing method of a foundation pit model testing device with controllable excavation, which comprises the following steps:
s1, finishing the construction of the base 1 by using iron plates and I-shaped steel. And welding a support baffle upright 6, a front upright 9 and a rear upright 10. And welding a side plate reinforcing rib 13, and inserting an organic glass side plate 11. The top of the front upright post 9 is welded with a front tie rod support 25, and the two ends of the front tie rod 24 are inserted into the slots of the front tie rod support 25. The back plate 12 is inserted and the back plate reinforcing ribs 14 are soldered. The supporting baffle 4 is inserted into the slot of the upright post 6 of the supporting baffle, and the reinforcing rib 5 of the supporting baffle is welded. Inserting a guard baffle 2 into an insertion slot of a front upright post 9, installing a support component steel base plate 3 on the guard baffle 2, installing a support component 7, installing a support baffle lateral connecting rod 8 to improve the deformation resistance of the guard baffle upright post, padding a waterproof membrane in a model box, welding a top settlement reference rod support 23, installing a top settlement reference rod 22, installing a top settlement dial indicator 21 on the top settlement reference rod 22 through a gauge stand, and completing the assembling work of the model box.
S2, before the model test is started, the enclosure baffle 2 is ensured to be installed stably, waterproof treatment is conducted on the two ends and the bottom of the enclosure baffle 2, the screw rod 27 of the supporting part 7 is pushed gradually by rotating the handle 26, and when the dial indicator 35 of the supporting part 7 has digital changes, the supporting part 7 and the enclosure baffle 2 are pushed up mutually. The data of the dial indicator 35 on all the support members 7 are recorded, this dial indicator 35 data being indicated with B1. Filling the simulated soil 15 into the model box, burying the micro soil pressure gauge 16 and the micro pore water pressure gauge 17 according to the test requirement in the soil filling process, leading out the sensor lead 18 from the side part of the model box to be connected with the signal acquisition instrument 19, and connecting the signal acquisition instrument 19 with the computer 20. After the filling is completed, the containment shield is deformed under the action of the soil pressure to push the supporting component 7, at this time, data of a dial indicator 35 on the supporting component 7 is changed, data of the dial indicator 35 at this time is recorded, the data of the dial indicator 35 is represented by B2, the elastic coefficient of the supporting component 7 is set to be k, supporting axial force F ═ k | (B2-B1) |, generated by the existing supporting component 7 under the action of the soil load outside the pit, the supporting axial force at this time is balanced with the soil pressure outside the pit, and the excavation of the foundation pit is simulated as long as the supporting component 7 at a certain layer is loosened.
S3, after the foundation pit is excavated, the deformation of the retaining baffle 2 needs to be known, the deformation measurement of the retaining baffle 2 of the foundation pit is divided into three conditions, the first is the deformation measurement of the excavated surface after the screw rod 27 of the supporting component 7 is loosened, the second is the deformation measurement of the supporting component 7 which is not loosened and is below the excavated surface, and the third is the deformation measurement when the screw rod 27 of the supporting component 7 is loosened and then screwed again.
In the first case, the deformation measurement of the enclosure baffle 2 needs to use a vernier caliper to measure the distance between the exposed end part of the screw rod 27 and the support baffle 4, namely, the jacking distance of the screw rod 27 is known by measuring the screwing thread of the screw rod 27. The exposed length of the screw rod 27 before loosening is S1, the reading variation of the dial indicator 35 of the front support part 7 when the screw rod 27 loosens is B2-B1, the screw rod 27 needs to be screwed again when the deformation of the enclosure baffle plate 2 at the moment needs to be measured, the screw rod 27 stops immediately when the reading of the dial indicator 35 changes, the exposed length of the screw rod 27 at the moment is recorded as S2, the moving distance of the screw rod 27 is S2-S1, the deformation of the enclosure baffle plate 2 is obtained by subtracting the thread B2-B1 for unloading the spring, and the deformation calculation formula of the enclosure baffle plate 2 at the first condition is (S2-S1) - (B2-B1). It should be noted that when the screw 27 is rested on the support element 7, the dial indicator 35 reading at this point is recorded as B3, theoretically B3 should be equal to B1, and Δ B should be B1-B3, which should be minimized during the test.
And in the second case, the deformation measurement of the enclosure baffle 2 is simpler, the data on the excavated dial indicator 35 is directly read and recorded as B3, and the deformation calculation formula of the enclosure baffle 2 in the second case is B3-B2.
The deformation measurement of the containment flap 2 in the third case is based on the first case, that is, the measurement in the first case is completed before the measurement in the third case. When the screw 27 is tightened again, the exposed length of the screw 27 at this time is recorded as S3, and the reading of the dial indicator 35 is B4, and the deformation amount of the enclosure fence 2 in the third case is (S3-S2) - (B4-B3) as compared with that in the first case. And adding the deformation amount of the enclosure baffle 2 in the first case, the deformation amount of the enclosure baffle 2 in the third case is S3-S1-B4-B2+ B3+ B1.
S4, when the erection of the support is to be simulated, the screw rod 27 of a certain support is screwed through the rotary handle 26, the dial indicator 35 is observed when the handle is rotated, the reading at the moment is recorded when the data of the dial indicator 35 starts to change, the data of the dial indicator 35 is still represented by B1, B2 is inversely calculated from the preset supporting shaft force F according to the supporting shaft force calculation formula F ═ k | (B2-B1) |, and the screw rod is stopped being screwed when the numerical value of the dial indicator 35 reaches B2, so that the erection of the support is completed.
S5, if the influence of the additional load outside the foundation pit on the deformation and the axial force of the foundation pit during the foundation pit model test is to be known, only the reading of the dial indicator 35 of the supporting component 7 is observed, the variation of the reading of the dial indicator 35 is the deformation of the enclosure baffle 2, and the variation of the axial force of the supporting component 7 can be obtained according to a calculation formula F ═ k | (B2-B1) |.
Claims (10)
1. The utility model provides a excavation controllable foundation ditch model test device which characterized in that: the device comprises a model box outer frame (39), simulated soil (15), a supporting baffle plate component (40), a supporting component (7) and a test instrument component;
the model box outer frame (39) mainly comprises a front upright post (9), a rear upright post (10), a containment baffle (2), an organic glass side plate (11), a back plate (12) and a front pull rod (24); the front upright post (9) is provided with a retaining baffle (2) and an insertion groove of an organic glass side plate (11); the front upright post (9) and the enclosure baffle (2) are fixed through screws; the rear upright post (10) is provided with a back plate (12) and an insertion groove of an organic glass side plate (11); a supporting component steel backing plate (3) is arranged between the supporting component (7) and the enclosure baffle (2); the back plate (12) is arranged between the two rear upright posts (10); the front pull rod (24) is arranged between the two front upright posts (9);
the supporting baffle plate component (40) mainly comprises a supporting baffle plate (4) and a supporting baffle plate upright post (6); two sides of the supporting baffle (4) are fixed through supporting baffle upright posts (6), and a supporting baffle side connecting rod (5) is arranged between the supporting baffle upright posts (6) and the front upright post (9);
the supporting part (7) mainly comprises a rotating handle (26), a screw rod (27), a supporting baffle screw rod fixing part (28), a sliding outer sleeve (29), a sliding inner sleeve (30), a spring inner sleeve (31), a spring outer sleeve (33) and a dial indicator (35); the spring inner sleeve (31) is arranged inside the spring outer sleeve (33), and the spring (38) is arranged inside the spring inner sleeve (31); a dial indicator (35) is arranged on the spring outer sleeve (33); one end of the screw rod (27) is propped against the outer end of the spring inner sleeve (31), and the other end is provided with a rotating handle (26); a support baffle screw rod fixing piece (28) is arranged on the support baffle (4), a sliding outer sleeve (29) is arranged on the inner side of the support baffle (4), a sliding inner sleeve (30) is arranged in the sliding outer sleeve (29), and the sliding inner sleeve (30) is welded at the outer end of a spring inner sleeve (31); the screw rod (27) is arranged in the support baffle screw rod fixing piece (28) and penetrates through the sliding outer sleeve (29) and the sliding inner sleeve (30) on the inner side of the support baffle (4);
the testing instrument assembly comprises a top settlement reference rod (22), a top settlement dial indicator (21), a micro soil pressure gauge (16), a micro pore water pressure gauge (17), a signal acquisition instrument (19) and a computer (20); the top settlement dial indicator (21) is placed on the top settlement reference rod (22) through an indicator seat, and the top settlement reference rod (22) is fixed above the outer frame (39) of the model box through a top settlement reference rod support (23); simulated soil (15) is laid in the model box, and a micro soil pressure gauge (16) and a micro pore water pressure gauge (17) are arranged in the simulated soil (15); the micro soil pressure gauge (16) and a sensor lead (18) of the micro pore water pressure gauge (17) are connected with a signal acquisition instrument (19), and the signal acquisition instrument (19) is connected with a computer (20).
2. The excavation-controllable foundation pit model test device of claim 1, wherein: the base (1) is formed by welding and splicing a plurality of steel plates and a plurality of I-shaped steel plates.
3. The excavation-controllable foundation pit model test device of claim 1, wherein: holes are distributed on the front upright post (9) and correspond to the holes on the edges of the two sides of the enclosure baffle (2); a side plate reinforcing rib (13) is arranged between the front upright post (9) and the rear upright post (10); the back plate (12) is provided with back plate reinforcing ribs (14).
4. The excavation-controllable foundation pit model test device of claim 1, wherein: the enclosure baffle (2) is made of an organic glass plate, and a drill hole is formed in the enclosure baffle (2); the support component steel backing plate (3) is connected with the enclosure baffle (2) through screws.
5. The excavation-controllable foundation pit model test device of claim 1, wherein: the simulated soil (15) is composed of gypsum, fly ash, sand, barite powder and water.
6. The excavation-controllable foundation pit model test device of claim 1, wherein: the supporting baffle upright post (6) is provided with a slot for fixing the supporting baffle; and the supporting baffle (4) is provided with a supporting baffle reinforcing rib (5).
7. The excavation-controllable foundation pit model test device of claim 1, wherein: a groove is formed in the side of the outer spring sleeve (33), a hole is formed in the end of the inner spring sleeve (31), and the limiting pin (34) penetrates through the groove and the hole; the outer end of the outer spring sleeve (33) is provided with a supporting part connecting end plate (37), and the outer end of the inner spring sleeve (31) is provided with an iron plate; the supporting component is connected with the end plate (37), the enclosure baffle (2) and the supporting component steel backing plate (3) through screws.
8. The excavation-controllable foundation pit model test device of claim 1, wherein: the spring outer sleeve (33) is provided with a dial indicator connecting piece (36), and the dial indicator (35) is arranged on the dial indicator connecting piece (36) through a screw; the exposed section of the spring inner sleeve (31) is provided with a displacement measuring plate (32), and a measuring head of the dial indicator (35) is propped against the displacement measuring plate (32).
9. An assembling and testing method of the excavation-controllable foundation pit model testing device of claim 1, characterized by comprising the following steps:
s1, completing construction of the base (1) by using an iron plate and I-shaped steel; welding a supporting baffle upright post (6), a front upright post (9) and a rear upright post (10) on the base (1); a side plate reinforcing rib (13) is welded between the front upright post (9) and the rear upright post (10), and an organic glass side plate (11) is inserted; a front pull rod support (25) is welded on the top of the front upright post (9), and two ends of the front pull rod (24) are inserted into slots of the front pull rod support (25); a back plate (12) is inserted between the two rear upright posts (10), and back plate reinforcing ribs (14) are welded; inserting a supporting baffle (4) into a slot of a supporting baffle upright post (6), and welding a supporting baffle reinforcing rib (5); inserting a guard baffle (2) into a slot of a front upright post (9), installing a support component steel backing plate (3) on the guard baffle (2), installing a support component (7) between the guard baffle (2) and the support baffle (4), and installing a support baffle side connecting rod (8) between a support baffle upright post (6) and the front upright post (9); a waterproof membrane is well padded in the model box, a top settlement reference rod support (23) is welded above the model box, then a top settlement reference rod (22) is installed, and a top settlement dial indicator (21) is installed on the top settlement reference rod (22) through a gauge stand, so that the assembling work of the model box is completed;
s2, before a model test is started, the enclosure baffle (2) is stably installed, waterproof treatment is conducted on the two ends and the bottom of the enclosure baffle (2), the screw rod (27) of the supporting component (7) is gradually pushed in by rotating the handle (26), and when the dial indicator (35) of the supporting component (7) has digital change, the supporting component (7) and the enclosure baffle (2) are mutually pushed; recording data of a dial indicator (35) on all support members (7), this dial indicator (35) data being indicated with B1; filling simulated soil (15) into the model box, burying a micro soil pressure gauge (16) and a micro pore water pressure gauge (17) in the soil filling process, leading a sensor lead (18) out of the side part of the model box to be connected with a signal acquisition instrument (19), and connecting the signal acquisition instrument (19) with a computer (20); after filling, the containment baffle is deformed under the action of soil pressure to push the supporting component (7), at the moment, data of a dial indicator (35) on the supporting component (7) is changed, data of the dial indicator (35) at the moment are recorded, the data of the dial indicator (35) are represented by B2, the elastic coefficient of the supporting component (7) is k, supporting shaft force F generated by the existing supporting component (7) under the action of soil mass load outside a pit is k (B2-B1), the supporting shaft force at the moment is balanced with the soil pressure outside the pit, and if excavation of a foundation pit is simulated, the supporting component (7) on a certain layer is loosened;
s3, after the foundation pit is excavated, the deformation of the enclosure baffle (2) is known, and the deformation measurement of the enclosure baffle (2) is divided into three conditions: the first is that the deformation of the excavation surface is measured after the screw rod (27) of the supporting component (7) is loosened; the second method is that the supporting part (7) is not loosened and the deformation under the excavation surface is measured; thirdly, the deformation measurement is carried out when the screw rod (27) of the supporting component (7) is loosened and then is screwed again;
s4, when the support erection is simulated, a screw rod (27) of a certain support is screwed through a rotating handle (26), a dial indicator (35) is observed when the handle is rotated, the reading at the moment is recorded when the data of the dial indicator (35) start to change, the data of the dial indicator (35) is still represented by B1, B2 is inversely calculated from the preset support axial force F according to the support axial force calculation formula F ═ k | (B2-B1) |, and the screw rod is stopped being screwed when the numerical value of the dial indicator (35) reaches B2, so that the support erection is completed;
and S5, observing the reading of a dial indicator (35) of the supporting component (7) to know the influence of the additional load outside the foundation pit on the deformation and the axial force during the foundation pit model test, wherein the variation of the reading of the dial indicator (35) is the deformation of the enclosure baffle (2), and the variation of the axial force of the supporting component (7) is obtained according to the calculation formula F ═ k | (B2-B1) |.
10. The assembling and testing method of the excavation-controllable foundation pit model testing device according to claim 9, characterized in that: in the step S3, in the first case, deformation of the enclosure baffle (2) is measured, a vernier caliper is used for measuring the distance between the exposed end part of the screw rod (27) and the support baffle (4), namely the jacking distance of the screw rod (27) is known by measuring the screwing thread of the screw rod (27); setting the exposed length of the lead screw (27) before loosening as S1, wherein the reading variation quantity of a dial indicator (35) of a front support part (7) of the lead screw (27) before loosening is B2-B1, tightening the lead screw (27) again when the deformation quantity of the enclosure baffle (2) at the moment is measured, stopping when the dial indicator (35) is screwed to have data variation, recording the exposed length of the lead screw (27) at the moment as S2, wherein the moving distance of the lead screw (27) is S2-S1, subtracting the deformation quantity of the enclosure baffle (2) by a thread B2-B1 of spring unloading, and setting the deformation calculation formula of the enclosure baffle (2) at the first condition as (S2-S1) - (B2-B1);
measuring the deformation of the enclosure baffle (2) under the second condition, directly reading data on the excavated dial indicator (35), and recording the data as B3, wherein the deformation calculation formula of the enclosure baffle (2) under the second condition is B3-B2;
the deformation measurement of the enclosure baffle (2) under the third condition is established on the basis of the first condition, namely the measurement under the first condition is firstly completed and then the measurement under the third condition is carried out; when the screw rod (27) is screwed again, the exposed length of the screw rod (27) at the moment is recorded as S3, the reading of the dial indicator (35) is B4, and the deformation of the enclosure baffle (2) in the third case is (S3-S2) - (B4-B3) compared with that in the first case; and adding the deformation amount of the enclosure baffle (2) in the first case, wherein the deformation amount of the enclosure baffle (2) in the third case is S3-S1-B4-B2+ B3+ B1.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105672379A (en) * | 2016-04-01 | 2016-06-15 | 浙江大学 | Foundation pit excavation model test device under dynamic artesian water action |
| CN105672378A (en) * | 2016-04-01 | 2016-06-15 | 浙江大学 | Foundation pit excavation model testing device simulating lifting of artesian head |
| CN105696636A (en) * | 2016-04-01 | 2016-06-22 | 浙江大学 | Foundation pit model testing device capable of simulating changes of groundwater level during excavation process of foundation pit |
| CN105716959A (en) * | 2016-04-01 | 2016-06-29 | 浙江大学 | Foundation pit model test device capable of simulating dynamic change of underground water level |
| CN105716960A (en) * | 2016-04-01 | 2016-06-29 | 浙江大学 | Foundation pit excavation model test device used in complicated groundwater environment |
| CN105842421A (en) * | 2016-04-01 | 2016-08-10 | 浙江大学 | Foundation pit model testing apparatus capable of simulating excavation process |
-
2021
- 2021-11-29 CN CN202111434519.7A patent/CN114199186B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105672379A (en) * | 2016-04-01 | 2016-06-15 | 浙江大学 | Foundation pit excavation model test device under dynamic artesian water action |
| CN105672378A (en) * | 2016-04-01 | 2016-06-15 | 浙江大学 | Foundation pit excavation model testing device simulating lifting of artesian head |
| CN105696636A (en) * | 2016-04-01 | 2016-06-22 | 浙江大学 | Foundation pit model testing device capable of simulating changes of groundwater level during excavation process of foundation pit |
| CN105716959A (en) * | 2016-04-01 | 2016-06-29 | 浙江大学 | Foundation pit model test device capable of simulating dynamic change of underground water level |
| CN105716960A (en) * | 2016-04-01 | 2016-06-29 | 浙江大学 | Foundation pit excavation model test device used in complicated groundwater environment |
| CN105842421A (en) * | 2016-04-01 | 2016-08-10 | 浙江大学 | Foundation pit model testing apparatus capable of simulating excavation process |
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