CN110424475B - Simulator for bulging deformation of long and narrow foundation pit under bias and seepage conditions - Google Patents
Simulator for bulging deformation of long and narrow foundation pit under bias and seepage conditions Download PDFInfo
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- CN110424475B CN110424475B CN201910614519.1A CN201910614519A CN110424475B CN 110424475 B CN110424475 B CN 110424475B CN 201910614519 A CN201910614519 A CN 201910614519A CN 110424475 B CN110424475 B CN 110424475B
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 223
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Classifications
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D33/00—Testing foundations or foundation structures
Abstract
A simulator for the uplift deformation of an elongated foundation pit under the conditions of bias and seepage comprises a model box, a foundation pit supporting system, a bias loading system, a water circulation and water level control system and a monitoring system; rammed soil is arranged in the model box, a foundation pit is arranged in the rammed soil, and a foundation pit supporting system is arranged in the foundation pit; the outside of the model box is provided with a bias loading system which pressurizes rammed earth outside the foundation pit; the water circulation and water level control system supplies water to the rammed earth in the model box and discharges water from the bottom of the foundation pit. According to the invention, the water head difference between the water level in the model box and the water level in the foundation pit is automatically controlled to simulate seepage conditions, so that the pressurization size and the pressurization distance of soil mass outside the foundation pit can be controlled in real time, the prestress of the retaining wall can be conveniently regulated, and the stress condition of the foundation pit engineering during excavation can be reflected more truly.
Description
Technical Field
The invention relates to a simulation device for the uplift deformation of a long and narrow foundation pit under the bias and seepage conditions, in particular to a model test device for foundation pit excavation by groundwater seepage generated by foundation pit excavation under the water-rich condition and the existence of bias load of the foundation pit; the method can be used for simulating the actual foundation pit excavation step and simulating three working conditions of stable seepage, bias and seepage bias coupling of the foundation pit; the displacement and deformation of the enclosure structure in the foundation pit excavation process and the problems of water and soil pressure change and foundation pit bottom soil body bulge deformation can be monitored.
Background
In practical engineering, the foundation pit is excavated, and plastic bulge is generated at the pit bottom due to various overloads on the periphery or water head difference generated by difference between the inside and the outside of the foundation pit, so that the foundation pit bulge is damaged, the engineering is safe, and serious economic loss is caused.
The present specification describes the calculation requirement of the foundation pit anti-uplift, but the principle of design calculation is simple, and the influence of factors of ballasting, seepage and coupling of bias seepage on the periphery of the foundation pit on the uplift deformation of the foundation pit is not considered. The design and calculation method should consider the above problems, and it is necessary to know the mechanism and rule of foundation pit bulge deformation by the coupling action of bias voltage, seepage and seepage bias voltage. At present, numerical software calculation is simplified on an engineering instance model, and the required soil body constitutive parameters are difficult to accurately measure, so that the influence on results is great, and the reference is low. Because the uncontrollable factors of the engineering field conditions are too many, and the soil body uplift displacement at the bottom of the foundation pit is mostly obtained by detecting the displacement of the lattice column as the soil body uplift displacement, the field monitoring data can not be really obtained at all.
The controllability of the foundation pit indoor scale model test is strong, and the obtained data can also be used for reversely calculating the deformation stress condition of the foundation pit of the actual engineering according to the scale ratio. However, no model test is currently considered by the learner to couple the over-bias and the seepage. At present, most of unbalanced load model tests are loaded with heavy objects, so that time and labor are wasted, the adjustability is poor, and the influence of the bias voltage and the bias voltage distance cannot be well implemented; for the foundation pit seepage model test, the water level difference is mostly controlled manually, and a great amount of time is also required to be continuously adjusted; the support is arranged in advance in the process of simulating foundation pit excavation, so that the stress and deformation conditions of the foundation pit in the actual excavation process cannot be truly simulated. There is no referenceable method for monitoring the deformation of the foundation pit bulge in the model test, and accurate monitoring of the bulge deformation is one of the keys of test data.
Therefore, the design has strong operability, can simulate the independent and coupling effects of different types of bias fields and seepage fields under different step-by-step excavation schemes of the foundation pit, and is used for accurately evaluating the foundation pit bulge deformation under the bias and seepage conditions, thereby having important significance for the design of the foundation pit supporting structure.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a simulation device for the uplift deformation of an elongated foundation pit under the conditions of bias and seepage.
The invention can simulate pit bottom uplift deformation under the independent and coupling actions of different types of bias fields and seepage fields under different step-by-step excavation schemes of the foundation pit, monitor the bending moment and deformation of the enclosure structure, the water and soil pressure change and the uplift displacement of the bottom of the foundation pit under three working conditions, and provide key information and parameters for researching the uplift deformation rule, analysis method and uplift stability measures of the foundation pit under the bias and seepage conditions.
The technical scheme adopted by the invention is as follows:
the utility model provides a simulation device of long and narrow foundation ditch uplift deformation under biasing and seepage flow condition which characterized in that: the device comprises a model box (1), a foundation pit supporting system (2), a bias loading system (3), a water circulation and water level control system (4) and a monitoring system (5); model soil is filled in the model box (1), a foundation pit is arranged in the model soil, and a foundation pit supporting system (2) is arranged in the foundation pit; the outside of the model box (1) is provided with a bias loading system (3), and the bias loading system (3) pressurizes model soil outside the foundation pit; the water circulation and water level control system supplies water to the model soil in the model box (1) and discharges water from the bottom of the foundation pit so as to simulate seepage of the foundation pit;
the upright post (3-5) of the bias loading system (3) is arranged outside the model box (1), a counter-force beam (3-4) erected on the upright post (3-5) spans over the foundation pit, the jack (3-6) can move on the counter-force beam (3-4), the jack is fixedly connected on the counter-force beam (3-4) through a first bolt (3-7) and a steel plate (3-3), and the lifting part of the jack (3-6) is connected with a load transmission plate (3-8);
the foundation pit supporting system (2) comprises a retaining wall (2-1), and a plurality of inner supporting units (2-2) are arranged between the opposite retaining walls (2-1);
the water circulation and water level control system (4) comprises a water storage tank (4-1), wherein a water suction pump (4-2-1) is arranged in the water storage tank (4-1), the water suction pump (4-2-1) is connected with a water inlet tank (4-2-4) through a first water pipe (4-2-3), the water inlet tank (4-2-4) is connected with two water inlet distribution pipe networks (4-2-7) arranged in the model tank (1) through a second water pipe (4-2-6), the two water inlet distribution pipe networks (4-2-7) are connected through a third water pipe (4-2-8), and a water through valve (4-2-5) and a first flowmeter (5-1) are arranged on the second water pipe (4-2-6); the drain pipe network (4-3-1) on the model soil surface at the bottom of the foundation pit is connected with a fifth water pipe (4-3-4) outside the model box (1) through a fourth water pipe (4-3-2), the fifth water pipe (4-3-4) is connected with the water storage tank (4-1), and the peristaltic pump (4-3-3) and the second flowmeter (5-2) are arranged on the fifth water pipe (4-3-4);
the monitoring system (5) comprises a first flowmeter (5-1), a second flowmeter (5-2), a tack (5-3), a second rubber film (5-4), a laser displacement meter (5-5), a strain type soil pressure box, a strain type pore water pressure sensor, a resistance strain gauge and a multi-channel data acquisition instrument; the resistance strain gauge is stuck to two side surfaces of the enclosure wall (2-1), and the strain type soil pressure box and the strain type pore water pressure sensor are buried in model soil of the model box (1); the strain type soil pressure box, the strain type pore water pressure sensor, the laser displacement meter and the resistance strain gauge are connected with the multichannel data acquisition instrument through signal transmission lines; the foundation pit bulge monitoring point comprises a tack (5-3) and a second rubber film (5-4), the second rubber film (5-4) is placed on model soil at the bottom of the foundation pit, and the tack (5-3) penetrates through the second rubber film (5-4) and is inserted into the soil. A laser displacement meter (5-5) arranged above the model box (1) detects the vertical depth of the bottom of the foundation pit where the tack (5-3) is located.
Preferably, the enclosure wall (2-1) is connected with the model box side plate (1-1) through the first rubber film (2-5).
Preferably, an upper probe and a lower probe for detecting the water level are arranged in the water inlet tank (4-2-4) and are respectively positioned at the water inlet head height h in The upper probe and the lower probe are connected with a water level controller (4-2-2) at the position of 10mm above and below, and the water level controller (4-2-2) is connected with the control end of a water pump (4-2-1).
Preferably, the inner supporting unit (2-2) comprises two supporting rods with internal threads at the ends, the two supporting rods are connected through threaded rods (2-4), and the other end of each supporting rod is propped against a bolt (2-3) of the enclosure wall (2-1).
Preferably, if the readings of the first flowmeter (5-1) and the second flowmeter (5-2) are equal, the seepage condition of the foundation pit is judged to be stable seepage.
The model system device adopted by the invention can simulate the foundation pit excavation process test under three working conditions:
(1) Bias conditions: applying vertical load to soil body at one side of the foundation pit through a pressure loading system to simulate the bias voltage, and regulating the position of a jack to simulate and control the bias voltage distance; the influence of different bias loads and bias distances on the stress and deformation of the foundation pit is obtained through the monitoring system.
(2) Seepage working condition: the water head difference inside and outside the foundation pit is controlled through the water circulation and water level regulating system, the seepage condition is generated, and the influence of the foundation pit on the stress and deformation of the foundation pit under the seepage condition is obtained through the monitoring system.
(3) Coupling conditions of bias seepage: before the foundation pit is excavated, a pressure loading device is used for realizing bias to soil body outside the foundation pit, the size of a pressurizing load is controlled through a jack, and the distance of bias loading is controlled through regulating and controlling the position of the jack; when the pressurization is stable, the foundation pit seepage condition is simulated through the water circulation and water level control system, so that the simulation of the coupling working condition of the bias voltage and seepage is realized.
The foundation pit bottom soil body uplift displacement monitoring device can monitor foundation pit bottom soil body uplift displacement by embedding soil body uplift monitoring points.
The beneficial effects of the invention are as follows:
1. the invention is provided with a water circulation and water level control system, and the seepage condition is simulated by automatically controlling the water level height in the model box and the water level difference of the water level height in the inner side of the foundation pit.
2. The vertical bias loading system at the outer side of the foundation pit can control the pressurizing size and the pressurizing distance of the soil body at the outer side of the foundation pit in real time.
3. The invention can simulate the actual excavation process of the foundation pit, and the support unit can achieve the aim of applying a certain prestress to the retaining wall by controlling the distance of the support unit screwed into the screw rod in the installation process; compared with a method for pre-installing the support on the retaining wall or fixing the support unit through the holes of the positioning telescopic rod in the excavation process, the method can more truly reflect the stress condition of the foundation pit engineering during excavation;
drawings
Fig. 1 is a frame view of a mold box of the present invention.
Fig. 2 (a) is a schematic diagram of a foundation pit support system.
Fig. 2 (b) is an elevation view of the foundation pit support system.
FIG. 3 is a schematic diagram of a bias loading system.
FIG. 4 is a schematic diagram of a foundation pit excavation model test apparatus with biased seepage.
Fig. 5 is a schematic diagram of a water inlet network.
Fig. 6 is a schematic diagram of a drainage network.
In the figure: a model box 1; a model box side plate 1-1; a model box bottom plate 1-2; 1-3 parts of water inlet holes; 1-4 parts of water outlet holes; a foundation pit support system 2; a wall 2-1; an inner support unit 2-2; 2-3 of bolts; 2-4 of threaded rods; 2-5 parts of a first rubber film; a bias loading system 3; reserving a bolt 3-1; a cross beam 3-2; 3-3 parts of steel plates; 3-4 of a counterforce beam; 3-5 of upright posts; 3-6 jacks; a first bolt 3-7; 3-8 of load transfer plates; a second bolt 3-9; a water circulation and level control system 4; a water storage tank 4-1; a water inlet control system 4-2; 4-2-1 of a water pump; a water level controller 4-2-2; 4-2-3 of a first water pipe; 4-2-4 parts of a water inlet tank; 4-2-5 of a water valve; 4-2-6 parts of a second water pipe; 4-2-7 of a water inlet distribution pipe network; a third water pipe 4-2-8; 4-3 of a horizontal drainage system; a drainage pipe network 4-3-1; fourth water pipe 4-3-2; peristaltic pump 4-3-3; fifth water pipe 4-3-4; a monitoring system 5; a first flowmeter 5-1; a second flowmeter 5-2; 5-3 parts of tack; a second rubber film 5-4; and 5-5 parts of a laser displacement meter.
Detailed Description
The invention will be further described with reference to the drawings and examples.
The simulator for the uplift deformation of the long and narrow foundation pit under the bias and seepage conditions comprises a model box (1), a foundation pit supporting system (2), a bias loading system (3), a water circulation and water level control system (4) and a monitoring system (5); model soil is filled in the model box (1), a foundation pit is arranged in the model soil, and a foundation pit supporting system (2) is arranged in the foundation pit; the outside of the model box (1) is provided with a bias loading system (3), and the bias loading system (3) pressurizes model soil outside the foundation pit; the water circulation and water level control system (4) supplies water to the model soil in the model box (1) and discharges water from the bottom of the foundation pit so as to simulate seepage of the foundation pit;
the upright post (3-5) of the bias loading system (3) is arranged outside the model box (1), a counter-force beam (3-4) erected on the upright post (3-5) spans over the foundation pit, the jack (3-6) can move on the counter-force beam (3-4), the jack is fixedly connected to the counter-force beam (3-4) through a first bolt (3-7) and a steel plate (3-3), and the lifting part of the jack (3-6) is connected with a load transmission plate (3-8);
the foundation pit supporting system (2) comprises a retaining wall (2-1), a plurality of inner supporting units (2-2) are arranged between the opposite retaining walls (2-1), each inner supporting unit (2-2) is a supporting rod with two inner threads at the end parts, and each supporting rod is connected with a threaded rod (2-4) through a built-in thread and is connected to a bolt (2-3) of the retaining wall (2-1);
the water circulation and water level control system (4) comprises a water storage tank (4-1), a water suction pump (4-2-1) is arranged in the water storage tank (4-1), the water suction pump (4-2-1) is connected with a water inlet tank (4-2-4) through a first water pipe (4-2-3), the water inlet tank (4-2-4) is connected with two water inlet distribution pipe networks (4-2-7) arranged in the model box (1) through a second water pipe (4-2-6), the two water inlet distribution pipe networks (4-2-7) are connected through a third water pipe (4-2-8), and a water through valve (4-2-5) and a first flowmeter (5-1) are arranged on the second water pipe (4-2-6); the drain pipe network (4-3-1) on the model soil surface at the bottom of the foundation pit is connected with a fifth water pipe (4-3-4) outside the model box (1) through a fourth water pipe (4-3-2), the fifth water pipe (4-3-4) is connected with the water storage tank (4-1), and the peristaltic pump (4-3-3) and the second flowmeter (5-2) are arranged on the fifth water pipe (4-3-4);
the monitoring system (5) comprises a first flowmeter (5-1), a second flowmeter (5-2), a tack (5-3), a second rubber film (5-4), a laser displacement meter (5-5), a strain type soil pressure box, a strain type pore water pressure sensor, a resistance strain gauge and a multi-channel data acquisition instrument; the resistance strain gauge is stuck to two side surfaces of the enclosure wall (2-1), and the strain type soil pressure box and the strain type pore water pressure sensor are buried in model soil of the model box (1); the strain type soil pressure box, the strain type pore water pressure sensor, the laser displacement meter and the resistance strain gauge are connected with the multichannel data acquisition instrument through signal transmission lines; the foundation pit bulge monitoring point comprises a tack (5-3) and a second rubber film (5-4), the second rubber film (5-4) is placed on model soil at the bottom of the foundation pit, and the tack (5-3) penetrates through the second rubber film (5-4) and is inserted into the soil. A laser displacement meter (5-5) arranged above the model box (1) detects the vertical depth of the bottom of the foundation pit where the tack (5-3) is located.
The first water pipe 4-2-3, the second water pipe 4-2-6, the third water pipe 4-2-8, the fourth water pipe 4-3-2 and the fifth water pipe 4-3-4 are all PVC pipes.
As shown in fig. 1, the model box (1) consists of four side plates (1-1) and a bottom plate (1-2); the side plates and the bottom plate are welded into a whole to form a cuboid model box with an open top surface, and the cuboid model box is used for filling and excavating a rock-soil body, embedding a foundation pit supporting system and embedding a monitoring system; the bottoms of two side plates of the model box are respectively provided with a water inlet hole (1-3) and a water outlet hole (1-4) which are used for connecting a water circulation and water level control system.
As shown in fig. 2 (a) and (b), the foundation pit supporting system (2) comprises a retaining wall (2-1) and an inner supporting unit (2-2); the enclosure wall (2-1) can be simulated by thin plates of different material types according to working condition requirements, and A multiplied by B bolts (2-3) are preinstalled on the enclosure wall and used for connecting the inner supporting unit (2-2); a first rubber film (2-5) for smearing vaseline is arranged between the enclosure wall and the model box, so that friction force between the enclosure wall and a side plate of the model box is eliminated, and mutual isolation of water and soil bodies on the inner side and the outer side of the enclosure wall is ensured; the inner supporting unit (2-2) can be simulated by hollow round bars of different material types according to working condition requirements; the inner supporting unit (2-2) is a supporting rod with internal threads at two ends, the two supporting rods are connected through a threaded rod (2-4), the other end of each supporting rod is propped against a bolt (2-3) of the enclosure wall (2-1), and the work of the inner supporting is simulated.
As shown in fig. 3, the bias loading system is composed of a ground reserved bolt (3-1), a cross beam (3-2), a steel plate (3-3), a counter-force beam (3-4) upright post (3-5), a jack (3-6), a first bolt (3-7), a load transmission plate (3-8) and a second bolt (3-9). The upright posts (3-5) are erected on the ground and fixedly connected with the ground reserved bolts (3-1); the beam (3-2) is welded at the top end of the upright post (3-5) and is at a certain distance from the top end, a plurality of bolt holes are reserved in the beam (3-2) at the top end, and the second bolts (3-9) can be screwed up through the bolt holes to fix the counter-force beam (3-4); the jack (3-6) is connected and fixed on the counterforce beam through a first bolt (3-7) and a steel plate (3-3); the load transfer plates (3-8) can be arranged below the hydraulic jack according to working conditions, and are used for applying load to the surface of the soil body outside the foundation pit.
As shown in FIG. 4, the water circulation and water level control system (4) consists of a water storage tank (4-1), a water inlet control system (4-2) and a horizontal drainage system (4-3). The water storage tank (4-1) is made of organic glass, the water suction pump (4-2-1) is arranged at the bottom of the water storage tank (4-1), the water storage tank is connected with the water inlet tank (4-2-4) of the water inlet control system (4-2) through the first water pipe (4-2-3), the top of the water storage tank (4-1) is provided with a water return hole, and the water storage tank is connected with the water discharge pipe network (4-3-1) through the fifth water pipe (4-3-4).
The water inlet control system (4-2) comprises a water suction pump (4-2-1), a water level controller (4-2-2), a first water pipe (4-2-3), a water inlet tank (4-2-4), a water through valve (4-2-5), a second water pipe (4-2-6), a water inlet distribution pipe network (4-2-7) and a third water pipe (4-2-8), wherein a water level controller probe is arranged at the inner side of the water inlet tank (4-2-4) and is respectively positioned at 10mm above and below the water inlet head height hin, and the water level controller (4-2-2) is used for controlling the water suction pump (4-2-1) to be opened and closed so as to simulate the water inlet head height hin; the water inlet distribution pipe network (4-2-7) (shown in figure 5) is formed by perforated PVC pipes wrapping geotextiles, the perforated PVC pipes are arranged on two sides of the inner wall of the model box (1), and the two pipe networks (4-2-7) are communicated through the third water pipe (4-2-8).
The horizontal drainage system (4-3) consists of a drainage pipe network (4-3-1), a fourth water pipe (4-3-2), a peristaltic pump (4-3-3) and a fifth water pipe (4-3-4). The drainage pipe network (4-3-1) (shown in figure 6) is formed by arranging an open pore PVC pipe wrapping geotechnical cloth on the surface of a soil body at the bottom of a foundation pit, the drainage pipe network (4-3-1) is communicated with the fourth water pipe (4-3-2), the drainage pipe network is communicated with the fifth water pipe (4-3-4) through a water outlet hole (1-4), the peristaltic pump (4-3-3) is arranged on the fifth water pipe (4-3-4), and the water level in the foundation pit is controlled to be kept at the pit bottom height through water pumping of the peristaltic pump (4-3-3).
As shown in a figure (4), the monitoring system (5) comprises a first flowmeter (5-1), a second flowmeter (5-2) tack (5-3), a second rubber film (5-4), a laser displacement meter (5-5), a strain earth pressure box, a strain pore water pressure sensor, a resistance strain gauge and a multi-channel data acquisition instrument; the strain type soil pressure box, the strain type pore water pressure sensor, the laser displacement meter (5-5) and the resistance strain gauge are connected with the multichannel data acquisition instrument through signal transmission lines. The large head nails (5-3) and the second rubber film (5-4) are foundation pit bulge monitoring arrangement points, the second rubber film (5-4) is placed with a soil carrying body to fill the bottom of the foundation pit and is compacted, the heads of the large head nails (5-3) are flat heads, the needle length is 2cm, and the large head nails penetrate through the second rubber film (5-4) and are inserted into the soil. The vertical depth of the foundation pit bottom where the tack (5-3) is located is measured by a laser displacement meter (5-5). The laser displacement meter (5-5) is arranged above the model box (1).
The working process of the invention is as follows:
the resistance strain gauges are stuck to the positions corresponding to the two side surfaces of the enclosure wall (2-1) at the root distance from the required measuring point, and are sealed and protected by AB glue, so as to monitor the bending moment change condition and conversion horizontal displacement of the enclosure wall (2-1) in the foundation pit excavation process; and filling soil into the model box layer by layer, and tamping layer by layer. And (3) placing the enclosure wall (2-1) into the model box after filling to the position where the enclosure wall (2-1) is placed, wherein the enclosure wall (2-1) is connected with the model box side plate (1-1) through a first rubber film (2-5), and the first rubber film is adhered to the model box by adopting 502 glue in a connection mode. When the model box soil body is filled and compacted to reach the bottom of the foundation pit in a preset mode, a second rubber film (5-4) is paved, a tack (5-3) is placed at the position where the uplift displacement of the foundation pit is required to be monitored, the tack is inserted into the soil body through the second rubber film, the vertical depth of the bottom of the tack foundation pit at the moment is monitored by a laser displacement meter (5-5), and the laser displacement meter (5-5) is fixed above the model box. And after the soil is arranged, continuing to fill the soil until the soil is finished. The strain type soil pressure box and the strain type pore pressure gauge are placed in the soil filling process according to the pre-designed positions. The strain gauge, the laser displacement meter (5-5), the strain earth pressure box and the strain pore pressure meter are communicated with the acquisition instrument through a lead.
When the operation is finished, standing for 24 hours, and then recording initial readings of all monitoring instruments; firstly, filling water into a water inlet tank (4-2-4), determining the water level height of the water inlet tank by determining the water level height of the outer side of a preset foundation pit, placing an upper probe and a lower probe of a water level controller (4-2-2) at the water level height of the water inlet tank (4-2-4), wherein the distance between the upper probe and the lower probe is 10mm, the upper probe is used for automatically stabilizing the water level of the water inlet tank, a water suction pump (4-2-1) is controlled by the water level controller (4-2-2) to automatically supplement water, a water through valve (4-2-5) is opened, and the water inlet tank (4-2-4) is filled with water into a model tank (1) through a second water pipe (4-2-6); when the water level of the water inlet water tank (4-2-4) is basically unchanged, the water level of the model box (1) is basically consistent with the water level of the water inlet water tank (4-2-4); the reading of each monitoring instrument to be recorded is stable and unchanged, the bias loading system (3) is used for pressurizing soil body outside the foundation pit, the magnitude of the pressurizing load of the jack (3-6) is controlled, and the distance of the bias loading is controlled; when the pressurization is stable, the reading of each monitoring instrument is stable and unchanged, the water in the foundation pit is reduced by a drainage system (4-3) preset in the foundation pit, and the water level in the foundation pit is controlled; meanwhile, water is supplemented into the model box (1) through the water inlet water tank (4-2-4) so that seepage is generated in the foundation pit. If the readings of the first flowmeter (5-1) and the second flowmeter (5-2) are equal, the seepage condition is judged to be stable seepage.
The method comprises the following steps of carrying out distributed excavation on the inner side of a foundation pit, slowly excavating soil on the inner side of a retaining wall (2-1) by a method of excavating and unloading the soil of the foundation pit, excavating to a position 2cm below a first support design position, and installing the first support, wherein the steps of installing the support are as follows: the two support rods are connected through a threaded rod (2-4), then one support rod is directly sleeved on a bolt (2-3) of the enclosure wall (2-1), the other support rod slowly rotates out of the threaded rod (2-4), is sleeved on the bolt (2-3) of the enclosure wall on the other side, and applies certain prestress to the enclosure wall; and (3) continuing to excavate the soil body after the first support is installed, installing the support by adopting the same method until the foundation pit is excavated to the position of the second rubber film (5-4) paved in advance, indicating that the foundation pit is excavated, measuring the depth of the tack (5-3) at the moment by using a laser displacement meter (5-5), and determining the uplift displacement of the soil body by the difference between the depth of the tack and the depth of the tack after excavation.
And in the whole foundation pit excavation process, the readings of the strain type soil pressure box, the strain type pore water pressure sensor, the laser displacement meter and the resistance type strain gauge are recorded through a data acquisition instrument.
The method comprises the steps of monitoring the change of water and soil pressure in the foundation pit in the excavation process, bending moment and displacement deformation conditions of an enclosure structure and the displacement of pit bottom uplift after excavation, arranging relevant test data to determine the problems of stress deformation of the foundation pit, development rules of pit bottom uplift deformation and the like, determining the influence factors of bias voltage and seepage on the problem of stability of the foundation pit uplift, and providing key information and parameters for the design of uplift-resistant measures. The above examples are a preferred embodiment of the present invention, and are further illustrative of the present invention and its application, and the present invention should not be construed as being limited to the above examples. All techniques implemented based on the principles and summary of the invention are within the scope of the invention.
Claims (5)
1. The utility model provides a simulation device of long and narrow foundation ditch uplift deformation under biasing and seepage flow condition which characterized in that: the device comprises a model box (1), a foundation pit supporting system (2), a bias loading system (3), a water circulation and water level control system (4) and a monitoring system (5); model soil is filled in the model box (1), a foundation pit is arranged in the model soil, and a foundation pit supporting system (2) is arranged in the foundation pit; the outside of the model box (1) is provided with a bias loading system (3), and the bias loading system (3) pressurizes model soil outside the foundation pit; the water circulation and water level control system supplies water to the model soil in the model box (1) and discharges water from the bottom of the foundation pit so as to simulate seepage of the foundation pit;
the upright post (3-5) of the bias loading system (3) is arranged outside the model box (1), a counter-force beam (3-4) erected on the upright post (3-5) spans over the foundation pit, the jack (3-6) can move on the counter-force beam (3-4), the jack is fixedly connected on the counter-force beam (3-4) through a first bolt (3-7) and a steel plate (3-3), and the lifting part of the jack (3-6) is connected with a load transmission plate (3-8);
the foundation pit supporting system (2) comprises a retaining wall (2-1), and a plurality of inner supporting units (2-2) are arranged between the opposite retaining walls (2-1);
the water circulation and water level control system (4) comprises a water storage tank (4-1), wherein a water suction pump (4-2-1) is arranged in the water storage tank (4-1), the water suction pump (4-2-1) is connected with a water inlet tank (4-2-4) through a first water pipe (4-2-3), the water inlet tank (4-2-4) is connected with two water inlet distribution pipe networks (4-2-7) arranged in the model tank (1) through a second water pipe (4-2-6), the two water inlet distribution pipe networks (4-2-7) are connected through a third water pipe (4-2-8), and a water through valve (4-2-5) and a first flowmeter (5-1) are arranged on the second water pipe (4-2-6); the drain pipe network (4-3-1) on the model soil surface at the bottom of the foundation pit is connected with a fifth water pipe (4-3-4) outside the model box (1) through a fourth water pipe (4-3-2), the fifth water pipe (4-3-4) is connected with the water storage tank (4-1), and the peristaltic pump (4-3-3) and the second flowmeter (5-2) are arranged on the fifth water pipe (4-3-4);
the monitoring system (5) comprises a first flowmeter (5-1), a second flowmeter (5-2), a tack (5-3), a second rubber film (5-4), a laser displacement meter (5-5), a strain type soil pressure box, a strain type pore water pressure sensor, a resistance strain gauge and a multi-channel data acquisition instrument; the resistance strain gauge is stuck to two side surfaces of the enclosure wall (2-1), and the strain type soil pressure box and the strain type pore water pressure sensor are buried in model soil of the model box (1); the strain type soil pressure box, the strain type pore water pressure sensor, the laser displacement meter and the resistance strain gauge are connected with the multichannel data acquisition instrument through signal transmission lines; the foundation pit bulge monitoring point comprises a tack (5-3) and a second rubber film (5-4), the second rubber film (5-4) is placed on model soil at the bottom of the foundation pit, and the tack (5-3) penetrates through the second rubber film (5-4) and is inserted into soil; a laser displacement meter (5-5) arranged above the model box (1) detects the vertical depth of the bottom of the foundation pit where the tack (5-3) is located.
2. A device for simulating the bulging deformation of an elongated foundation pit under biased and percolation conditions as set forth in claim 1, wherein: the enclosure wall (2-1) is connected with the model box side plate (1-1) through a first rubber film (2-5).
3. A device for simulating the bulging deformation of an elongated foundation pit under biased and percolation conditions as set forth in claim 1, wherein: in the water inlet tank (4-2-4)An upper probe and a lower probe for detecting the water level are respectively positioned at the water inlet head height h in The upper probe and the lower probe are connected with a water level controller (4-2-2) at the position of 10mm above and below, and the water level controller (4-2-2) is connected with the control end of a water pump (4-2-1).
4. A device for simulating the bulging deformation of an elongated foundation pit under biased and percolation conditions as set forth in claim 1, wherein: the inner supporting unit (2-2) comprises two supporting rods with internal threads at the ends, the two supporting rods are connected through threaded rods (2-4), and the other end of each supporting rod is propped against a bolt (2-3) of the enclosure wall (2-1).
5. A device for simulating the bulging deformation of an elongated foundation pit under biased and percolation conditions as set forth in claim 1, wherein: if the readings of the first flowmeter (5-1) and the second flowmeter (5-2) are equal, judging that the seepage condition of the foundation pit is stable seepage.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202393607U (en) * | 2011-11-28 | 2012-08-22 | 同济大学 | Underground digging simulation test box |
| CN103487563A (en) * | 2013-07-12 | 2014-01-01 | 华北水利水电大学 | Testing apparatus used for simulating foundation pit three-dimensional seepage caused by combined effects of separating-lowering-pouring and ground deformation mechanism |
| CN104099953A (en) * | 2013-04-08 | 2014-10-15 | 同济大学 | Centrifugal model testing device for simulating pressure water head change and stability of foundation pit |
| CN105672379A (en) * | 2016-04-01 | 2016-06-15 | 浙江大学 | Foundation pit excavation model test device under dynamic artesian water action |
| CN105716960A (en) * | 2016-04-01 | 2016-06-29 | 浙江大学 | Foundation pit excavation model test device used in complicated groundwater environment |
| CN108316366A (en) * | 2018-03-19 | 2018-07-24 | 浙江大学城市学院 | A kind of multi-functional foundation pit model assay systems equipment and its application method |
| CN211113788U (en) * | 2019-07-09 | 2020-07-28 | 浙江工业大学 | Simulation device for bulging deformation of long and narrow foundation pit under bias pressure and seepage conditions |
-
2019
- 2019-07-09 CN CN201910614519.1A patent/CN110424475B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202393607U (en) * | 2011-11-28 | 2012-08-22 | 同济大学 | Underground digging simulation test box |
| CN104099953A (en) * | 2013-04-08 | 2014-10-15 | 同济大学 | Centrifugal model testing device for simulating pressure water head change and stability of foundation pit |
| CN103487563A (en) * | 2013-07-12 | 2014-01-01 | 华北水利水电大学 | Testing apparatus used for simulating foundation pit three-dimensional seepage caused by combined effects of separating-lowering-pouring and ground deformation mechanism |
| CN105672379A (en) * | 2016-04-01 | 2016-06-15 | 浙江大学 | Foundation pit excavation model test device under dynamic artesian water action |
| CN105716960A (en) * | 2016-04-01 | 2016-06-29 | 浙江大学 | Foundation pit excavation model test device used in complicated groundwater environment |
| CN108316366A (en) * | 2018-03-19 | 2018-07-24 | 浙江大学城市学院 | A kind of multi-functional foundation pit model assay systems equipment and its application method |
| CN211113788U (en) * | 2019-07-09 | 2020-07-28 | 浙江工业大学 | Simulation device for bulging deformation of long and narrow foundation pit under bias pressure and seepage conditions |
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