CN105784562A - Transparent soil test device used for simulating seepage of foundation pit dewatering confined aquifer underground water - Google Patents

Abstract

The invention relates to a transparent soil test device use for simulating seepage of foundation pit dewatering confined aquifer underground water.The transparent soil test device use for simulating seepage of foundation pit dewatering confined aquifer underground water comprises a model casing, a cover plate arranged in the model casing, a plank simulating a concrete diaphragm wall, water tank elements connected on both sides of the model casing to control confined groundwater level, and a piezometer tube system used for measuring the water pressure of strata of different depths and arranged on the backface of the model casing.Compared with the existing technology, the seepage paths of water flows around a waterproof curtain can be directly observed, and seepage path rules, seepage velocity and other relevant parameters can be accurately analyzed through photos shot by a high-speed camera; and seepage laws of distances between different concrete diaphragm walls and the plane and the section of a filter tube can be obtained by changing the insertion ratio of the concrete diaphragm walls and the length of a pumping filtering pipe.

Description

Transparent soil test device for simulating groundwater seepage in dewatering confined aquifers of foundation pits

technical field

The invention belongs to the technical field of foundation pit dewatering engineering, in particular to a transparent soil test device for simulating groundwater seepage in a foundation pit dewatering confined aquifer.

Background technique

With the rapid development of my country's economy, urbanization has been carried out across the country. In order to meet the growing needs of citizens for basic functions such as travel, rail transit transfers, commerce, and parking, especially in dense urban centers where land use is increasingly tight , the development and utilization of underground space has become an irresistible trend. As an important part of underground engineering, foundation pit engineering is constantly expanding in scale, from small shallow foundation pits to ultra-deep and super-large areas. Especially in the most economically developed Yangtze River Delta region, due to the relatively high groundwater level, foundation pit precipitation must be carried out before foundation pit excavation. However, the impact of large-scale, large-scale, and long-term precipitation on the surrounding geological environment cannot be ignored. . Therefore, how to improve the dewatering efficiency of foundation pits and how to effectively prevent the impact of dewatering on the surrounding geological environment has become the focus of attention of the engineering community and many scholars, and it is also an urgent problem to be solved in the current stage of engineering construction.

In view of the fact that the reliability of the numerical simulation method to guide engineering practice is closely related to the input material parameters, the actual measurement scheme is not repeatable, and it is difficult to reveal the influence of a certain parameter on the foundation pit dewatering project. Model test is a kind of It is an important means to study the mechanism of foundation pit precipitation. Chinese patent CN105369812A discloses a method for determining the confined water level of a foundation pit under a suspended water-stop curtain for constant flow pumping. On the basis of obtaining the soil layer information of the confined aquifer and the pumping information, according to Darcy's law and the principle of water conservation, Aiming at the internal fixed flow pumping process of the foundation pit, determine the groundwater level when the water stop curtain does not enter the aquifer and the change value of the ground water level caused by the water stop curtain, so as to determine the inner and outer bearings of the foundation pit when the internal fixed flow rate of the foundation pit is pumped under the suspended water stop curtain Pressurized water level. However, this patent does not disclose the structure of the specific experimental device used, and cannot realize the simulation of groundwater seepage in the dewatering confined aquifer of the foundation pit.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned defects in the prior art and provide the simulation of the seepage path that can directly observe the water flow around the water-stop curtain, and accurately analyze the law of the seepage path and the related parameters such as the seepage velocity through the photos taken by the high-speed camera. Transparent soil test device for groundwater seepage in the dewatering confined aquifer of the foundation pit; by changing the insertion ratio of the ground connection wall, the length of the pumping filter pipe, and the plane and section distances between the ground connection wall and the filter pipe, the seepage law.

The purpose of the present invention can be achieved through the following technical solutions:

The transparent soil test device for simulating the seepage of groundwater in the confined aquifer of foundation pit precipitation, including:

model box,

The cover plate set in the model box, the plank of the simulated ground connecting the wall,

The water tank assembly connected to both sides of the model box to control the water level of the pressurized water,

A system of piezometric pipes for measuring water pressure at various depths of the formation, connected to the back of the model box.

The cover plate includes a middle cover plate and side cover plates arranged on both sides of the middle cover plate.

The middle cover plate is a hollow structure, the center of the upper surface is provided with an opening, and the lower surface is provided with openings for arranging simulated pumping well pipes.

A tracer hole for installing a tracer tube is opened on the side cover.

The simulated pumping well pipe is a steel pipe equipped with a filter screen, which is connected to the opening on the lower surface of the middle cover plate.

The middle cover plate and the side cover plates arranged on both sides of the middle cover plate are all covered on the plank of the simulated ground connecting wall.

The surface of the plank of the simulated ground connection wall is polished, and the bottom is zigzag.

The water tank assembly is composed of a water tank, a water pipe, and a threaded steel rod,

The lower part of the water tank is provided with two openings, one of which communicates with the model box through a water pipe, and the other communicates with the outside, and the two openings are separated by a glass plate.

The water tank is sleeved on the threaded steel rod and moves up and down along the thread of the steel rod.

The back of the model box is provided with a steel plate, and pressure measuring holes are evenly distributed on the steel plate, and each pressure measuring hole is sealed by a solid plastic short rod.

The piezometric tube system is composed of planks, glass tubes and Mig paper,

The glass tube is embedded in the groove opened on the wooden board, and the glass tube is connected to the pressure measuring hole on the back of the model box through the leather tube for water pressure measurement, and the MiG paper is pasted on the wooden board behind the glass tube Indicates the scale.

Compared with the prior art, the present invention has the following advantages:

1. Can directly observe the seepage path of the water flow around the water-stop curtain;

2. Accurately analyze the seepage path law and seepage velocity and other related parameters through the photos taken by the high-speed camera;

3. By changing the insertion ratio of the ground connection wall, the length of the pumping filter pipe, and the seepage law of the plane and section distance between the ground connection wall and the filter pipe;

4. The device can be reused after use;

5. It can reveal the influence law of a certain parameter on the foundation pit dewatering project.

Description of drawings

Fig. 1 is the front view structure schematic diagram of the present invention;

Fig. 2 is the rear view structure schematic diagram of the present invention;

Fig. 3 is the top view structure schematic diagram of model box;

Fig. 4 is the structural representation of side cover plate;

Fig. 5 is a top view structural schematic diagram of the middle cover plate;

Fig. 6 is a schematic bottom view of the middle cover;

Fig. 7 is the structural representation of water tank;

Fig. 8 is the structural schematic diagram of the plank of simulating ground connection wall;

Fig. 9 is a structural schematic diagram of the pressure measuring tube system.

In the figure, 1-model box, 2-water tank, 3-water pipe, 4-threaded steel rod, 5-side cover plate, 6-wooden board simulating the ground wall, 7-middle cover plate, 8-pressure measuring hole, 9-water pumping hole, 10-tracer hole, 11-well pipe hole, 12-pumping well pipe, 13-wooden board, 14-glass tube, 15-groove, 16-Mig paper.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example

Example

A transparent soil test device for simulating seepage of groundwater in a confined aquifer for foundation pit dewatering, the structure of which is shown in Figure 1-2. The test device includes a model box 1, a water tank 2, a water pipe 3, a threaded steel rod 4, and a cover plate 5. The middle cover plate 7, the wooden board 6 for simulating the ground wall, the pumping well pipe 12, the wooden board 13, the glass tube 14, the MiG paper 16 and other components. The model box 1 is rectangular, and its structure is shown in Figure 3. Its left and right side walls and front side walls are made of tempered glass, and the rear side wall is made of steel plates. The pressure measuring hole 8. Simultaneously seal the pressure measuring hole 8 with a solid plastic short rod of considerable diameter, just pull out the solid plastic short rod if the hole pressure of a certain point is to be measured, and be connected with the glass tube 14 in the pressure measuring tube system by a leather tube. The structure of the piezometric tube system is shown in Figure 9. It consists of planks 13, glass tubes 14 and Mig paper 16. The glass tube 14 is to be connected with the plank 13 by being embedded in the plank protrusion of the groove 15, and sticking MiG paper 16 on the plank 13 behind the glass tube 14 to represent the scale. The glass tube 14 is connected to the pressure measuring hole 8 on the back of the model box 1 through the leather tube to complete the measurement of the water pressure.

The schematic diagram of the structure of the cover plates on both sides inside the model box is shown in Figure 4; three tracer holes 10 with a diameter of 5mm are arranged on the side cover plates 5 on both sides, which are used to install the tracer tubes, and in the test The tracer is injected through the tracer tube.

The structure of the middle cover plate 7 inside the model box is shown in Figure 5-6. Model box 1 interior is designed with two cover plates 5 on both sides and the middle cover plate 7 in the middle, and the middle cover plate 7 top center has the pumping hole 9 that diameter is 20mm, and the bottom is interval 25mm, the well pipe hole 11 of diameter 7mm ( For arranging pumping well pipes), the middle height is a hollow thickness of 5mm. Before the test, a steel pipe with an inner diameter of 6mm and an outer diameter of 7mm is installed in the required well pipe hole 11 according to the design working conditions, and a 200-mesh filter screen is added to form The pumping well pipe 12 and the pumping hole 9 are provided with metal valves, which are opened during the test and connected to a peristaltic pump through a leather tube for pumping.

The structure diagram of the water tank on the side of the model box is shown in Figure 7; there are two holes in the lower part of the water tank 2, one of which is connected to the inside of the model box 1 through a water pipe 3, and the other hole is connected to the outside, and is connected to a small water pump during the test. Inject the test liquid. A glass plate with a certain height is arranged in the middle of the water tank 2 to isolate the two holes. The height of the water tank 2 can be adjusted through the threaded steel rod 4, so that the initial water level of the pressurized water can be controlled in the test.

The schematic diagram of the structure of the plank simulating the ground connecting wall inside the model box is shown in FIG. 8 ; the bottom of the plank 6 simulating the ground connecting wall is zigzag, and the surface is polished.

Claims (10)

1. the transparent soil assay device of simulation base pit dewatering artesian aquifer seepage action of ground water, it is characterised in that this device includes:

Model casing,

It is arranged on the plank of the cover plate in model casing, simulation ground-connecting-wall,

It is connected to model casing both sides, controls the cistern assembly of artesian water water level,

Measure the pressure-measuring pipe system of the hydraulic pressure on the stratum of different depth, be connected to the back side of model casing.

2. the transparent soil assay device of simulation base pit dewatering artesian aquifer seepage action of ground water according to claim 1, it is characterised in that described cover plate includes inter panel and is arranged on the side cover plate of inter panel both sides.

3. the transparent soil assay device of simulation base pit dewatering artesian aquifer seepage action of ground water according to claim 2, it is characterised in that

Described inter panel is hollow form structure, and upper surface center is provided with perforate, and lower surface is provided with arranges the perforate simulating the well casing that draws water,

Described side cover plate offers the tracer hole installing tracer pipe.

4. the transparent soil assay device of simulation base pit dewatering artesian aquifer seepage action of ground water according to claim 3, it is characterised in that the described simulation well casing that draws water is the steel pipe installing filter screen additional, is connected between in the perforate that cover plate lower surface is offered.

5. the transparent soil assay device of simulation base pit dewatering artesian aquifer seepage action of ground water according to claim 1, it is characterised in that described inter panel and be arranged on the side cover plate of inter panel both sides and all cover on the plank being located at simulation ground-connecting-wall.

6. simulate the transparent soil assay device of base pit dewatering artesian aquifer seepage action of ground water according to claim 1 or 5, it is characterised in that the board surface of described simulation ground-connecting-wall is through polishing, and bottom is zigzag.

7. the transparent soil assay device of simulation base pit dewatering artesian aquifer seepage action of ground water according to claim 1, it is characterised in that described cistern assembly is by water tank, water pipe, and threaded rod iron forms,

The bottom of described water tank offers two perforates, and one of them perforate, through water pipe and model casing UNICOM, another perforate and ft connection, separates through glass plate between two perforates.

8. the transparent soil assay device of simulation base pit dewatering artesian aquifer seepage action of ground water according to claim 7, it is characterised in that described water tank cover is located on threaded rod iron, and the screw thread along rod iron moves up and down.

9. the transparent soil assay device of simulation base pit dewatering artesian aquifer seepage action of ground water according to claim 1, it is characterized in that, the back side of described model casing is provided with steel plate, and on this steel plate, average mark is furnished with pressure tap, and each pressure measurement aperture solid plastic stub seals.

10. the transparent soil assay device of simulation base pit dewatering artesian aquifer seepage action of ground water according to claim 9, it is characterised in that described pressure-measuring pipe system is made up of plank, glass tubing and rice ruled paper,

Described glass tubing is embedded in the groove offered on plank, and this glass tubing is connected with the pressure tap at model casing back is carried out water-pressure survey by leather hose, and described rice ruled paper is attached on the plank of glass tubing behind expression scale.