Device for promoting drainage of soft foundation through air jet large-range joint cutting

Abstract

The utility model belongs to the technical field of soft soil foundation treatment, and particularly relates to a device for promoting soft foundation drainage through air jet large-range joint cutting, which comprises an air compressor and an air inlet channel connected with an outlet of the air compressor, the end of each desilting pressurizing pipe is provided with a telescopic desilting pressurizer, jet flow of jet flow nozzles at the ends of the telescopic desilting pressurizers forms a communicated jet flow channel, a plastic drainage plate is arranged between every two adjacent desilting pressurizing pipes, and the tops of the multiple plastic drainage plates are connected through drainage channels. According to the plastic drainage plate dredging and pressurizing device, the problem that the plastic drainage plate is blocked by sludge in the using process is effectively solved, and the drainage period is shortened.

Description

Technical Field

[0001] The utility model belongs to the technical field of soft soil foundation treatment, and particularly relates to a device for promoting soft foundation drainage by large-range air jet slitting. Background Technique

[0002] Soft soil is widely distributed in China. It has high water content, weak water permeability, rheological properties, large void ratio, and low shear strength. The foundation composed of soft soil is generally weak, with poor water permeability, bearing capacity, strength, stability, and easy to move, etc., which cannot meet the needs of engineering. Therefore, pre-treatment is required before construction on soft soil foundation. Currently, common methods for soft soil foundation treatment include cement mixing piles, gravel piles, sand bag wells, plastic drainage plates, etc.

[0003] The cement mixing pile is a method that uses a deep mixing machine to take cement slurry or cement powder as a curing agent and forcibly mixes the soft soil and the curing agent deep in the foundation to form a composite foundation, improving the bearing capacity of the foundation and reducing the foundation settlement. However, this method has high costs, difficult quality control, and great interference to underground facilities. The gravel pile uses gravel (pebble) with no bonding strength as the main material. After forming a hole in the soft foundation by vibration, impact or water flushing, the gravel (pebble) is then extruded into the soil hole to form a dense pile body composed of large-diameter gravel. The composite foundation composed of gravel (pebble) piles and the soil between piles is used for reinforcement. However, this method has low compaction effect, small lateral pressure for compaction of the soil on the pile side, and poor reinforcement effect on the soil between piles. Both the sand bag well method and the plastic drainage plate method are layout methods of vertical drainage systems. The sand bag well method is to place loose sand into slender bags made of chemical fiber textiles and place them in soft soil to drain the pore water in the soft soil foundation, reducing the consolidation time and improving the bearing capacity of the soft soil foundation. The plastic drainage plate method is to use plastic drainage plates to increase the vertical drainage path of the soil layer, shorten the drainage distance, and accelerate the consolidation of the foundation. The plastic drainage plate method is simple in construction, reliable in quality, and fast in speed. In recent years, it is gradually replacing the sand bag well method and becoming the most widely used vertical drainage material.

[0004] However, during the process of using plastic drainage plates for drainage consolidation, there is always the problem of silt blocking the drainage plates, which greatly affects the drainage efficiency. Using plastic drainage plates for soft foundation treatment has advantages such as low cost and remarkable effect. Clearing silt and quickly draining water is an important means to improve its drainage efficiency and save the construction period. Therefore, the utility model herein proposes a device for promoting soft foundation drainage by automatic air jet slitting. Content of the Utility Model

[0005] The purpose of the utility model is to provide a device for promoting soft foundation drainage by large-range air jet slitting, which can effectively solve the problem of silt blocking during the use of plastic drainage plates and reduce the drainage period.

[0006] To achieve the above object, the technical solution adopted by the utility model is as follows:

[0007] An air jet large-range slitting device for promoting soft foundation drainage, comprising an air compressor, an air inlet channel connected to the outlet of the air compressor, a plurality of silt cleaning and pressure increasing pipes evenly spaced on the air inlet channel, and a telescopic silt cleaning and pressure increasing device provided at the end of each silt cleaning and pressure increasing pipe. The jet nozzles at the ends of the plurality of telescopic silt cleaning and pressure increasing devices form a connected jet channel. The jet channel is formed by high-speed jets impacting the silt. Under the experimental condition of 2 Mpa, the maximum distance of the impact jet can reach more than 80 cm, meeting the need for silt cleaning of drainage boards. A plastic drainage board is provided between adjacent silt cleaning and pressure increasing pipes. The tops of the plurality of plastic drainage boards are connected through a drainage channel, and the outlet of the drainage channel is connected to the inlet of a sump. The plastic drainage board, the silt cleaning and pressure increasing pipe, and the sump are all arranged in the soil below the ground.

[0008] Further, the telescopic silt cleaning and pressure increasing device includes a fixed section and a telescopic section, and the fixed section and the telescopic section are fixedly connected through a fixing member. A forward drill bit is provided at the end of the telescopic section. It also includes an air path pipe provided at the center. The air inlet end of the air path pipe is communicated with the air inlet channel. An upper exhaust port symmetrically arranged obliquely backward is provided at the connection between the forward drill bit and the telescopic section. A lower exhaust port opposite to the exhaust direction of the upper exhaust port is also included. Gyro sensors are respectively provided at the upper and lower positions inside the forward drill bit between the upper exhaust port and the lower exhaust port. Air valves are respectively provided on the air channels of the upper exhaust port and the lower exhaust port. The gyro sensors and the air valves are both electrically connected to a controller.

[0009] Further, a plurality of asymmetrically arranged air jet nozzles are provided on the front end face of the forward drill bit. The jet direction of each air jet nozzle is tangential to the front end face of the forward drill bit. After ventilation, high-speed gas gushes out from the nozzle outlet, forming a stable channel to achieve the purpose of silt cleaning and drainage. The jet nozzles are arranged asymmetrically, and the forward drill bit can maintain a rotating state by relying on the reaction force of the high-speed gas at the nozzle outlet, thereby increasing the silt cleaning area.

[0010] Further, the flow channel of the air jet nozzle is successively a contraction section, a throat section, and a diffusion section from the inlet to the outlet. The air jet nozzle adopts a multi-stage acceleration principle. After high-pressure gas enters the nozzle, it continuously accelerates in the contraction section, and then continues to accelerate to supersonic speed in the diffusion section after passing through the throat section. The maximum speed of the gas can reach 2.6 Mach. The shape of the nozzle outlet is designed as a circle, having a larger silt cleaning area.

[0011] Furthermore, the plastic drainage board includes a vertically arranged hollow core board and permeable holes evenly arranged on the core board. A layer of filter membrane is provided on each permeable hole. The plastic drainage board is a vertical drainage component inserted into the soft soil foundation by a plug-in machine, having vertical internal gaps and lateral pores. The core board is made by mixing and preparing polypropylene (PP) and polyethylene (PE), and has the rigidity of polypropylene, the flexibility and weather resistance of polyethylene; the filter membrane is made of long-fiber thermally bonded non-woven fabric, with water immersion resistance and extremely excellent water seepage performance. It has the advantages of good integrity, high tensile strength, and large filter membrane pore size. The pore size of the filter membrane of this board can be adjusted according to the silt particle size, and the equivalent pore size of the filter membrane is generally less than 75μm to achieve the best purpose of mud-water separation.

[0012] After the whole equipment is installed, check the air tightness of the pipeline and the interface. After confirming that there is no error, turn on the air compressor and set the air compressor parameters. When the pressure reaches 10 Mpa, the air compressor stops working. When the pressure is lower than 10 Mpa, it automatically pressurizes. The gyroscope sensor feeds back the position and movement speed of the forward drill bit to the controller, and the controller controls the opening and closing of the upper and lower exhaust port valves, so that the forward drill bit works back and forth between the predetermined depth and the lowest depth; when starting to work, the gyroscope sensor feeds back that the current position of the forward drill bit has not reached the predetermined depth, and the controller controls the upper exhaust port to open and the lower exhaust port to close to provide power for the downward movement of the forward drill bit; if it has reached the predetermined depth, the controller controls the upper exhaust port to close and the lower exhaust port to open, and the forward drill bit obtains the power for upward movement until it reaches the lowest depth. The maximum gas volume allowed to pass through the air valve is 0.2 kg / s. Due to the high-speed self-rotation of the forward drill bit after ventilation, the resistance during downward movement is small. To achieve an ideal dredging effect, control the lower air outlet to close, and the air outlet volume of the upper air outlet is less than 0.05 kg / s, and the downward movement speed of the forward drill bit is less than 0.1 m / s; after reaching the predetermined depth, the forward drill bit moves upward. Since the resistance during upward movement is large, to improve the dredging efficiency, control the air outlet volume of the lower air outlet to be greater than 0.15 kg / s, and the upper air outlet to close, and the upward movement speed of the forward drill bit is greater than 0.2 m / s.

[0013] The advantages of the present utility model are:

[0014] 1. This soft foundation treatment device is based on the low-pressure air jet technology. Compared with other gas injection methods such as vacuum preloading, the gas source pressure is low (the maximum is 2 MPa), the device is simple, and it has the advantages of low energy consumption, low cost, and environmental protection;

[0015] 2. This soft foundation treatment device can effectively solve the problems in the process of using plastic drainage boards, and remove the silt blocking the drainage boards through air jets, so as to achieve the purpose of reducing the drainage cycle;

[0016] 3. The soft foundation treatment device has a simple structure and a wide application range. It can achieve large-scale silt cleaning under the condition of large burial depth. After setting the parameters of the controller, relying on the gyroscope sensor in the controller, it can control the opening and closing of the upper and lower air outlet valves according to the position and movement state of the forward drill bit. Generally, the forward drill bit keeps moving forward and returns after reaching the predetermined depth, and then makes repeated up and down movements within a certain range along the telescopic rod direction, realizing unmanned and fully automatic silt cleaning. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is the front view structural schematic diagram of the device of the present utility model.

[0018] Figure 2 is the top view structural schematic diagram of the device of the present utility model.

[0019] Figure 3 is the structural schematic diagram of the telescopic silt cleaning booster pump in the present utility model.

[0020] Figure 4 is the schematic diagram of the air jet nozzle in the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] Such as Figures 1-4As shown in the figure, a device for promoting soft foundation drainage by large-range slitting of air jets includes an air compressor 1, an intake passage 6 connected to the outlet of the air compressor. The air compressor is connected to the intake passage to continuously supply high-pressure gas to the telescopic silt-removing supercharger. An intake main valve 2 is provided in the intake passage of the air compressor to control the air supply into the pipeline. A plurality of silt-removing booster pipes are evenly spaced on the intake passage. Each end of the silt-removing booster pipe is provided with a telescopic silt-removing supercharger 8. The jet nozzles 17 at the ends of the plurality of telescopic silt-removing superchargers form a connected jet channel 9. The jet channel is formed by high-speed jets impacting the silt. Under the experimental condition of 2 Mpa, the maximum distance of the impact jet can reach more than 80 cm, meeting the need for silt removal of drainage boards. A plastic drainage board 7 is provided between adjacent silt-removing booster pipes. The tops of the plurality of plastic drainage boards are connected through a drainage channel 5. The catch basin is connected to the main drainage channel. Under the action of the air-liquid dual-purpose pump 4, the water discharged from the plastic drainage board converges into the main pipe through the branch drainage channel and flows to the catch basin. The outlet of the drainage channel is connected to the inlet of the catch basin 3. The plastic drainage board includes a vertically arranged hollow core board and water-permeable holes evenly arranged on the core board. A layer of filter membrane is provided on each water-permeable hole. The plastic drainage board is a vertical drainage component inserted into the soft soil foundation through a plate inserter, having vertical internal gaps and lateral pores. The core board is made of a mixture of polypropylene (PP) and polyethylene (PE), having the rigidity of polypropylene, the flexibility and weather resistance of polyethylene. The filter membrane is made of long-fiber thermally bonded non-woven fabric, having water immersion resistance and extremely excellent water seepage performance. It has the advantages of good integrity, high tensile strength, and large filter membrane pore size. The filter membrane of this board can adjust the pore size according to the silt particle size. The equivalent pore size of the filter membrane is generally less than 75 μm to achieve the best mud-water separation purpose. The plastic drainage board, silt-removing booster pipe, and catch basin are all arranged in the soil below the ground. The telescopic silt-removing supercharger includes a fixed section 10 and a telescopic section 13, and the fixed section and the telescopic section are fixedly connected through a fixing member 12. The end of the telescopic section is provided with a forward drill bit 19. It also includes an air pipeline 11 arranged in the center. The intake end of the air pipeline is communicated with the intake passage. An upward exhaust port 16 is symmetrically arranged obliquely backward at the connection between the forward drill bit and the telescopic section. It also includes a downward exhaust port 17 opposite to the exhaust direction of the upward exhaust port. A gyroscope sensor 14 is respectively arranged at the upper and lower positions inside the forward drill bit between the upward exhaust port and the downward exhaust port. Air valves 15 are respectively arranged on the air channels of the upward exhaust port and the downward exhaust port. The gyroscope sensor and the air valve are both electrically connected to the controller. The front end face of the forward drill bit is provided with a plurality of asymmetrically arranged air jet nozzles 18. The jet direction of each air jet nozzle is tangential to the front end face of the forward drill bit. After ventilation, high-speed gas gushes out from the nozzle outlet, forming a stable channel to achieve the purpose of silt removal and drainage. The jet nozzles are asymmetrically placed, and the reaction force of the high-speed gas at the nozzle outlet provides power for the rotation of the forward drill bit. In the ventilated state, the forward drill bit can maintain a rotating state, thereby increasing the silt removal area.The flow channel of the air jet nozzle is successively a contraction section 21, a throat section 22, and a diffusion section 23 from the inlet 20 to the outlet 24. The air jet nozzle adopts the principle of multi-stage acceleration. After the high-pressure gas enters the nozzle, it continuously accelerates in the contraction section first, and then continues to accelerate to supersonic speed in the diffusion section after passing through the throat. The maximum gas speed can reach 2.6 Mach. The shape of the nozzle outlet is designed to be circular, with a relatively large silt cleaning area.

[0022] A drainage method for a device that promotes soft foundation drainage by large-range slitting with air jets includes the following steps:

[0023] S1. First, insert plastic drainage boards into the soft soil foundation. The distribution principle of the silt cleaning booster and the plastic drainage boards is usually designed and planned according to the size of the soft soil foundation area to be treated, and the layout and installation spacing of the silt cleaning booster and the plastic drainage boards are designed according to actual needs. After laying a sand cushion layer on the pretreatment site, insert the plastic drainage boards and drive multiple sump wells. Bury them according to a drainage board spacing of 0.9 m and a plastic drainage board exposed length of not less than 50 cm.

[0024] S2. Install telescopic silt cleaning boosters within the area where the plastic drainage boards are arranged. Let the gas volume passing through the nozzle outlet per unit time be Q 1 , which is determined by the cross-sectional area of the throat of the air jet nozzle; n is the number of silt cleaning boosters, mainly determined by the exhaust volume of the air compressor; the number of air nozzles carried by a single silt cleaning booster is 6; considering the loss a of the gas during the gas path transmission, the design and planning are based on the air compressor exhaust volume Q = 2n·Q 1 ·(1 - a) to calculate the quantity;

[0025] S3. Calculate the gas reaction force F and set the parameters of the gyroscope sensor. The calculation formula for F is F = M q ·V out +(P out -P a )S out , where M q is the gas mass flow rate unit kg / s, V out is the gas velocity unit m / s at the air outlet, P out is the gas pressure Pa at the air outlet, Pa is the atmospheric pressure Pa outside the air outlet, S out is the cross-sectional area of the air outlet m 2 . After fixedly connecting the silt cleaning booster pipe to the telescopic silt cleaning booster, lay it at the set position;

[0026] S4. Lay the drainage channel, connect adjacent two plastic drainage boards, and collect them to the main drainage channel pipe. The water flow finally leads to the sump well for treatment. Install the air compressor, lay the gas path, connect the telescopic silt cleaning booster and install the main intake valve;

[0027] S5. Check the airtightness of the pipeline and interfaces. After confirmation, start the air compressor and set the parameters of the air compressor. When the pressure reaches 10 Mpa, the air compressor stops working. When the pressure is lower than 10 Mpa, it automatically pressurizes. The gyroscope sensor feeds back the position and movement speed of the advancing drill bit to the controller, and the controller controls the opening and closing of the upper and lower exhaust port valves, so that the advancing drill bit works back and forth between the predetermined depth and the lowest depth;

[0028] S6. When starting to work, the gyroscope sensor feeds back that the position of the current advancing drill bit has not reached the predetermined depth. The controller controls the upper exhaust port to open and the lower exhaust port to close to provide power for the downward movement of the advancing drill bit; if it has reached the predetermined depth, the controller controls the upper exhaust port to close and the lower exhaust port to open, and the advancing drill bit obtains the power for upward movement until it reaches the lowest depth. The maximum gas volume allowed to pass through the air valve is 0.2 kg / s. Due to the high-speed rotation of the advancing drill bit after ventilation, the resistance during downward movement is small. To achieve an ideal dredging effect, control the lower air outlet to close and the air volume of the upper air outlet to be less than 0.05 kg / s, and the descending speed of the advancing drill bit is less than 0.1 m / s; after reaching the predetermined depth, the advancing drill bit moves upward. Since the resistance during upward movement is large, to improve the dredging efficiency, control the air volume of the lower air outlet to be greater than 0.15 kg / s and the upper air outlet to close, and the ascending speed of the advancing drill bit is greater than 0.2 m / s.

[0029] During specific use, first use a drill to drill to the design depth in the soft soil foundation to be treated, install the dredging booster and plastic drainage plates according to the pre-planned arrangement method, and connect the telescopic dredging booster and plastic drainage plates to the air inlet channel and drainage channel respectively. Turn on the air compressor and set the parameters of the air compressor. When the pressure is higher than 10 Mpa, the air compressor stops working. When the pressure is lower than 10 Mpa, it automatically pressurizes. Continuously turn on the air compressor to inject gas into the air circuit. After the high-pressure gas enters the dredging booster, it first enters the air jet nozzle. The high-pressure gas continuously accelerates to supersonic speed inside the nozzle, and the silt can be knocked away and the seam can be cut at the nozzle outlet to form a jet channel; at the same time, the reaction force of the high-speed jet can provide rotational power for the advancing drill bit, so that the advancing drill bit maintains a rotating state in the ventilated state, thereby removing the silt blocking the plastic drainage plate and achieving the purpose of rapid drainage consolidation. When starting to work, the gyroscope sensor senses that the advancing drill bit is stationary and automatically opens the air valve to control the upper air outlet to intake air. The advancing drill bit moves downward along the telescopic rod under the action of the reaction force; when the gyroscope sensor senses that the nozzle moves to the predetermined depth, it automatically closes the upper air outlet and opens the lower air outlet. At this time, the advancing drill bit moves upward along the telescopic rod under the reaction force. The entire process automatically circulates. By changing the parameters of the gyroscope sensor, the expected dredging effect can be achieved under different working conditions.

Claims

1. A device for promoting drainage of soft foundation by large-scale cutting of air jets, characterized in that: It includes an air compressor, an air intake channel connected to the air compressor outlet, a plurality of silt removal and boosting pipes are evenly spaced on the air intake channel, a telescopic silt removal and boosting device is provided at the end of each silt removal and boosting pipe, jets from jet nozzles at the ends of the plurality of telescopic silt removal and boosting devices form a connected jet channel, a plastic drain board is provided between adjacent silt removal and boosting pipes, the plastic drain board includes a vertically arranged hollow core board and water-permeable holes evenly arranged on the core board, and a layer of filter membrane is provided on each water-permeable hole; the tops of the plurality of plastic drain boards are connected through a drainage channel, the outlet of the drainage channel is connected to the inlet of a water collection well through a gas-liquid dual-purpose pump, the plastic drain board, the silt removal and boosting pipes and the water collection well are all arranged in the soil below the ground, and the telescopic silt removal and boosting device is electrically connected to a controller.

2. The device for promoting soft foundation drainage by large-scale air jet cutting as claimed in claim 1, characterized in that: The telescopic dredging booster includes a fixed section and a telescopic section, and the fixed section and the telescopic section are fixedly connected by a fixing piece, an advancing drill bit is provided at the end of the telescopic section, and also includes an air pipeline arranged in the center, the air inlet end of the air pipeline is connected with the air inlet channel, an upper exhaust port is provided at the connection between the forward drill bit and the telescopic section, and also includes a lower exhaust port which is symmetrically arranged obliquely backward, and also includes a lower exhaust port which is opposite to the exhaust direction of the upper exhaust port, a gyroscope sensor is respectively provided at the upper and lower positions inside the forward drill bit between the upper exhaust port and the lower exhaust port, and also includes air valves respectively arranged on the airways of the upper exhaust port and the lower exhaust port, and the gyroscope sensor and the air valve are both electrically connected to the controller.

3. The device for promoting soft foundation drainage by large-scale air jet cutting as claimed in claim 1, characterized in that: The front end face of the forward drill bit is provided with a plurality of asymmetrically arranged air jet nozzles, and the jetting direction of each air jet nozzle is arranged tangentially to the end face of the forward drill bit.

4. The device for promoting soft foundation drainage by large-scale air jet cutting as claimed in claim 3, characterized in that: The air jet nozzle flow channel comprises a contraction section, a throat section and an expansion section from the inlet to the outlet.

5. The device for promoting soft foundation drainage by large-scale air jet cutting as claimed in claim 4, characterized in that: The maximum air volume of the air valve is 0.2kg / s. When the forward drill bit moves downward, the air volume of the upper exhaust port is less than 0.05kg / s, and the forward drill bit descending speed is less than 0.1m / s; when the forward drill bit moves upward, the air volume of the lower exhaust port is greater than 0.15kg / s, and the forward drill bit rising speed is greater than 0.2m / s.

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