Vacuum negative pressure drainage system and treatment method for soft soil foundation

Abstract

A vacuum negative-pressure drainage system for a soft soil foundation comprises a drainage well, a vacuum negative-pressure drainage device and a pressurizing gas injection device, the vacuum negative-pressure drainage device and the pressurizing gas injection device are arranged in the soft soil foundation in a staggered mode in the horizontal direction, and a siphon connector, a drainage opening and a siphon drainage connector are arranged on the surface of the vacuum negative-pressure drainage device. The drainage port is connected with a drainage pipe, the drainage pipe is connected with a second drainage pipe, the second drainage pipe enables the multiple drainage pipes to be communicated and gathered together through a connector and to be communicated with the drainage well, the siphon drainage connector is connected with a siphon drainage pipe, and the siphon drainage pipe is connected with a main siphon drainage pipe. The vacuum negative pressure drainage device and the pressurization gas injection device are matched, pore water in the soil body is rapidly drained through the negative pressure effect formed by vacuum, the pressure of the pore water is reduced, the soil body is solidified, the effective stress of the soil body is improved, the bearing capacity of a foundation is enhanced, the better construction effect is achieved, and the foundation treatment cost is effectively reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of soft soil foundation treatment methods, and specifically relates to a soft soil foundation vacuum negative pressure drainage system and treatment method Background Art

[0002] Buildings (structures) constructed on soft soil foundations often have many problems caused by uneven settlement after construction. Soft soil foundation treatment has always been a difficult problem in academia and engineering. The lateral displacement of settlement after construction directly affects the safe use of the project. Effective reinforcement of soft soil foundations is an important measure to reduce the lateral displacement of settlement after construction, accelerate the consolidation of soft soil, reduce settlement after construction, reduce water content, and improve the shear strength of soil. Commonly used methods include vacuum preloading method, pile loading consolidation method, etc.

[0003] The traditional vacuum preloading method for dewatering is composed of a series of equipment such as a consolidation system air compressor, a vacuum generator, and a water vapor separator. If the on-site construction is connected in series, the vacuum degree of the vacuum preloading consolidation system will be insufficient, resulting in poor vacuum preloading drainage effect. At the same time, the secondary preloading treatment requires a long construction period, a large amount of sand, and a high overall cost. In addition, since the vacuum preloading is carried out in series, the vacuum loss will gradually increase when the vacuum pressure is transmitted to the underground, resulting in different degrees of solidification treatment of the soft soil layer at different depths due to different vacuum pressures, resulting in poor land consolidation effect, requiring repeated treatments, low efficiency, and increased costs.

[0004] After searching, the invention with publication number CN107419717A provides a pressurized compound vacuum preloading soft soil foundation treatment construction device and process. The drainage board inserted in the soft soil foundation is composed of a core board and a special non-woven filter membrane. The special non-woven filter membrane and the core board are thermally bonded by a hot-melt composite machine to form an integral plastic drainage board. The integral plastic drainage board is connected to the vacuum pipe network of the horizontal drainage system through a steel wire hose and a closed butterfly-type joint. The steel wire hose adapts to the uneven settlement formed when the site is vacuumed, and the vacuum is directly transmitted to the inside of the drainage board through the integral plastic drainage board and the butterfly-type joint, thereby reducing the vacuum loss along the way. Several pressurized drainage boards are also inserted in the soft soil foundation. The upper ends of the pressurized drainage boards are connected to the pressurized pipe network through the vacuum pipe sealing section to form a newly added inflation pressurization system. The pressurized drainage board is negatively pressurized by the pressurized pipe network in the early stage and positively pressurized in the later stage. The operation is relatively cumbersome, and the problem that different vacuum pressures have different degrees of solidification treatment of soft soil layers at different depths is not solved. Summary of the invention

[0005] In order to solve the problem that the above-mentioned traditional vacuum preloading method adopts a series connection method, etc., which will cause the vacuum loss to gradually increase when the vacuum pressure is transmitted to the underground, resulting in different degrees of solidification treatment of the soft soil layer at different depths due to different vacuum pressures, resulting in poor land consolidation effect, the present invention proposes a vacuum negative pressure drainage system and treatment method for soft soil foundation to solve the above-mentioned problem.

[0006] A vacuum negative pressure drainage system for a soft soil foundation comprises a drainage well, a vacuum negative pressure drainage device and a pressurized gas injection device, wherein the vacuum negative pressure drainage device and the pressurized gas injection device are alternately arranged in a soft soil foundation in a horizontal direction, a siphon pipe joint, a drainage port and a siphon pipe drainage joint are arranged on the surface of the vacuum negative pressure drainage device, the drainage port is connected to a drainage pipe, the drainage pipe is connected to a second drainage pipe, the second drainage pipe connects and collects a plurality of the drainage pipes together through a joint and connects to the drainage well, the siphon pipe drainage joint is connected to the siphon drainage pipe, the siphon drainage pipe is connected to a main siphon drainage pipe, the main siphon drainage pipe connects and collects a plurality of the siphon drainage pipes together through a joint and connects to the drainage well, and a water outlet end of the main siphon drainage pipe extends under the water surface of the drainage well; the vacuum negative pressure drainage device and the pressurized gas injection device cooperate to use the negative pressure formed by vacuum to quickly discharge pore water in the soil, reduce the pore water pressure, consolidate the soil, increase the effective stress of the soil, enhance the bearing capacity of the foundation, have a better construction effect, and effectively reduce the foundation treatment cost.

[0007] Furthermore, an air inlet is provided on the surface of the vacuum negative pressure drainage device, the air inlet is connected to a pressurized air inlet pipe, and the pressurized air inlet pipe is connected to a high-pressure air pump;

[0008] Furthermore, the drainage well is equipped with a first drainage pipe, which is connected to a drainage pump; the seepage water flow is gathered in the middle inner cavity inside the vacuum negative pressure drainage device to produce a sealing effect, and then the water inside the water collection cavity is pumped out through the water pump booster drainage effect or the siphon effect of the drainage pipe, thereby producing a vacuum negative pressure drainage effect.

[0009] Furthermore, the vacuum negative pressure drainage device includes a pressure-resistant shell, the surface of the upper half of the pressure-resistant shell is surrounded by a water filter infiltration net, an annular partition is installed inside the pressure-resistant shell, an annular inner cavity is arranged between the pressure-resistant shell and the annular partition, an intermediate inner cavity is arranged inside the annular partition, a water collecting cavity is arranged below the annular partition, the water collecting cavity connects the intermediate inner cavity and the annular inner cavity, the drainage pipe extends into the pressure-resistant shell until the insertion end reaches the water collecting cavity, the drainage port and the siphon pipe joint are located at the top of the pressure-resistant shell, the siphon pipe drainage joint is located at the bottom of the pressure-resistant shell, and the siphon pipe drainage joint, the siphon pipe joint and the annular inner cavity are connected.

[0010] Furthermore, the pressurized air injection device includes a pressure-resistant and breathable shell, the surface of which is evenly provided with air holes, baffles are provided inside the pressure-resistant and breathable shell, the baffles are arranged in a staggered manner, and a device air intake pipe is installed inside the pressure-resistant and breathable shell, and the device air intake pipe is connected to the pressurized air intake pipe.

[0011] Furthermore, a water pump is installed in the middle inner cavity, a pipe connected to the water inlet of the water pump extends into the water collecting cavity, and a water outlet of the water pump is connected to a drain pipe.

[0012] Furthermore, a plurality of the vacuum negative pressure drainage devices are arranged in soil layers at different depths to form at least two interconnected structures, and the siphon drainage pipe connects the siphon drainage joints and siphon joints on the surfaces of the adjacent vacuum negative pressure drainage devices; when the soft soil layer is deep, in order to compensate for the problem of different vacuum negative pressures generated by vacuum drainage at different depths, a siphon drainage combined with a vacuum negative pressure drainage device is used to connect the upper and lower layers of the vacuum negative pressure drainage device. Compared with the traditional loading consolidation method, the seepage direction inside the soil is from bottom to top, and the seepage mode needs to overcome the effect of gravity. The seepage direction of the new siphon combined with vacuum preloading method is from top to bottom, so there is no need to overcome the effect of gravity. Instead, gravity plays a role in promoting seepage, thereby accelerating the drainage of the soil and promoting the consolidation of the soil.

[0013] Furthermore, the siphon pipe drainage joint, the siphon pipe joint, the drainage port and the pipe connection are all provided with sealing members, so as to enhance the sealing performance inside the device and ensure the normal operation of the device.

[0014] Furthermore, the surface of the soft soil base layer is covered with a sealing film, and a pile carrier is arranged above the sealing film.

[0015] Furthermore, a film pressing trench is dug around the soft soil foundation, the film edge of the sealing film is pressed into the film pressing trench, and then the film pressing trench is backfilled.

[0016] Furthermore, the vacuum negative pressure drainage device and the pressurized gas injection device are cylindrical in shape, and a liquid level sensor is arranged inside the vacuum negative pressure drainage device; the cylindrical shape can better adapt to drilling and disperse the pressure at the same time. The liquid level sensor is arranged and cooperates with the water pump to improve the drainage efficiency when necessary.

[0017] A construction method for a vacuum negative pressure drainage system for a soft soil foundation comprises the following steps:

[0018] S1: The soft soil foundation site is pre-leveled before construction, and cement soil mixing piles or steel sheet piles are used as sealing curtains around to ensure the sealing effect of the soft soil solidification treatment area;

[0019] S2: Arrange measuring points in the soft soil solidification treatment area, arrange settlement points on the side of the soft soil area, and use a one-hole multi-point burial method to lay out layered settlement meters and pore water pressure gauges, and lay out deep horizontal displacement inclinometers at the center point of the side.m;

[0020] S3: Staggered drilling holes are made in the soft soil layer, and the number of vacuum negative pressure drainage devices and pressurized gas injection devices is determined according to the size of the soft soil area. Before the vacuum negative pressure drainage devices and pressurized gas injection devices are placed in the soft soil layer, a water-permeable membrane is wrapped around the outside of the vacuum negative pressure drainage devices and pressurized gas injection devices. After completion, the vacuum negative pressure drainage devices and pressurized gas injection devices are placed in the soft soil layer;

[0021] X1: When the soft soil layer is shallow, a single layer of vacuum negative pressure drainage device is set in the soft soil layer at the same depth, and a main siphon drainage pipe is pre-buried under the vacuum negative pressure drainage device and the siphon drainage port and the main siphon drainage pipe are connected by the siphon drainage pipe;

[0022] X2: When the soft soil layer is deep, the vacuum negative pressure drainage device is set in the soil layers of different depths to form at least two layers of interconnected structures. When connecting, the siphon pipe joints and siphon drainage outlets on the surfaces of adjacent vacuum negative pressure drainage devices are connected through siphon drainage pipes, and a pre-total siphon drainage pipe is excavated deep in the soft soil layer;

[0023] S4: A drainage well is excavated next to the soft soil solidification treatment area, and the main siphon drainage pipe is connected to the siphon drainage pipe through a joint and discharged into the drainage well. At the same time, the booster air intake pipe is connected to the air inlet of the booster air injection device and connected to the air intake pipe of the device;

[0024] S5: a pressurized gas injection device is arranged in the middle of the vacuum negative pressure drainage device;

[0025] S6: Connect the second drain pipe to each drain pipe through a joint, and extend the output end of the second drain pipe into the drain well, install the first drain pipe in the drain well, connect the first drain pipe to the drain pump, and connect the boost intake pipe to the high-pressure air pump.

[0026] Working principle: After the construction and installation of the vacuum negative pressure drainage system for soft soil foundation is completed, the high-pressure air pump is started, and the high-pressure air is transmitted to the inside of the booster air injection device through the booster air intake pipe, so that the internal pressure of the booster air injection device is greater than the pressure of the external soft soil layer. The high-pressure compressed air enters the gaps in the soft soil layer through the vents evenly arranged on the surface of the pressure-resistant and breathable shell and squeezes the gap water, so that the gap water moves in the direction away from the booster air injection device;

[0027] Since the booster gas injection device and the vacuum negative pressure drainage device are arranged alternately, after the booster gas injection device is started, the pressure in the soft soil layer is greater than the pressure inside the vacuum negative pressure drainage device. Under the action of the pressure difference, the gap water passes through the water filter infiltration net and enters the annular cavity, and finally collects in the water collection cavity at the bottom of the vacuum negative pressure drainage device. The annular cavity and the middle cavity are connected through the water collection cavity to form a communicating vessel. At the same time, the vacuum negative pressure drainage device is placed underground, and the interior of the device is in a sealed state.

[0028] When the water content in the soft soil layer is low, the water level in the water collection chamber continues to rise and reaches the siphon drainage outlet. Under the action of gravity, the water will flow along the siphon drainage outlet into the siphon drainage pipe. When the vacuum negative pressure drainage device is arranged in a single layer, the siphon drainage pipe and the main siphon drainage pipe are connected and merged into the drainage well.

[0029] When the water content in the soft soil layer is high, the diameter of the siphon drainage pipe is thinner and the drainage speed is slower. When the water level continues to rise, the air in the middle cavity is continuously compressed. When the air pressure in the middle cavity is greater than the external atmospheric pressure, a pressure difference is formed. The water in the water collection cavity will spontaneously flow outward through the drainage pipe until the air pressure in the middle cavity is equal to the external atmospheric pressure. Due to the effect of the water in the bottom water collection cavity, a sealing effect will be continuously produced to ensure that the entire vacuum negative pressure drainage device continues to exist in a vacuum negative pressure environment. At the same time, due to the siphon connection effect, the vacuum negative pressure is ensured to increase continuously, which speeds up the processing speed of the vacuum negative pressure drainage device. When the water level rises again and the air pressure in the middle cavity is greater than the external atmospheric pressure, a pressure difference is formed, and the drainage process is repeated.

[0030] When the water content in the soft soil layer is high and the soft soil layer is deep, the vacuum negative pressure drainage device is connected to multiple layers for use. The siphon drain port of the vacuum negative pressure drainage device on the upper layer is connected to the siphon pipe joint of the vacuum negative pressure drainage device on the lower layer, and the siphon drain port of the vacuum negative pressure drainage device on the bottom layer is connected to the main siphon drain pipe. When the booster gas injection device is started, the water in the water collecting chamber inside the vacuum negative pressure drainage device on the upper layer will be transported to the inside of the vacuum negative pressure drainage device on the lower layer through the siphon drain pipe under the action of gravity until it is transmitted to the vacuum negative pressure drainage device on the bottom layer. Since the vacuum negative pressure drainage device on the bottom layer is not only subject to the pressure generated by the booster gas injection device, but also to the gravity of the soil layer and the ballast body, the internal and external pressure difference of the vacuum negative pressure drainage device on the bottom layer is large, and at the same time, it also needs to receive the water flow out of the vacuum negative pressure drainage device on the upper layer, so that the water flow inside the vacuum negative pressure drainage device on the bottom layer rises very quickly. At this time, the autonomous drainage efficiency relying solely on the pressure difference is low. The staff can install a water pump inside the vacuum negative pressure drainage device on the bottom layer. When the water level exceeds a certain limit, the liquid level sensor is triggered and the water pump is started to improve the drainage efficiency.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The combination of siphon drainage and vacuum negative pressure drainage can generate a sealing effect through the convergence of seepage water flow, and then pump water through the pressurized drainage effect or siphon effect to directly generate a vacuum negative pressure drainage effect, directly avoiding the problem of insufficient vacuum degree of the consolidation device of the vacuum preloading method, resulting in poor vacuum preloading drainage effect, and further improving the drainage efficiency. Especially when the soft soil layer is deep, the multi-layer connected vacuum negative pressure drainage device can use gravity to accelerate the transmission and discharge of water flow, avoiding the traditional heap consolidation method. The seepage direction inside the soil body is from bottom to top, and the seepage mode needs to overcome the gravity. The seepage direction of the new siphon combined vacuum preloading method is from top to bottom, so there is no need to overcome the gravity. Gravity instead plays a role in promoting seepage. At the same time, the use of water pumps and liquid level sensors can provide additional drainage power when necessary to ensure the continuity and efficiency of the drainage process.

[0033] 2. An efficient drainage network is formed by staggered arrangement of vacuum negative pressure drainage devices and booster gas injection devices. Booster intake pipes are alternately arranged in the vacuum negative pressure drainage device. When the efficiency of the vacuum negative pressure drainage device decreases in the middle and late stages, intermittent boosting construction is performed through the booster intake pipe. Compressed gas is used to disturb the soft soil layer within a certain depth range, breaking the relative equilibrium state between the soft soil layers during vacuum negative pressure, making it easier to discharge more water between the soft soil layers. Under the action of the booster gas injection device, the interstitial water in the soft soil layer is effectively squeezed and directed to the vacuum negative pressure drainage device, achieving rapid drainage. This process not only reduces the pore water pressure, but also promotes the consolidation of the soil, thereby increasing the effective stress of the soil.

[0034] 3. The construction method is simple and easy, and has strong adaptability to soft soil foundation sites. Through pre-leveling, measurement point arrangement, drilling and device installation, etc., the soft soil foundation can be accurately treated. At the same time, the setting of sealing film and film pressing groove effectively ensures the sealing effect of the treatment area and avoids interference from external factors.

[0035] 4. Through scientific design and construction, this soft soil foundation vacuum negative pressure drainage system achieves efficient drainage and reinforcement of soft soil foundation. It does not completely require the use of loading method, which reduces the use of sand to a certain extent, shortens the construction period and reduces the overall cost, thus shortening the construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1It is a structural schematic diagram of a vacuum negative pressure drainage system for soft soil foundation;

[0038] Figure 2 for Figure 1 Enlarged view of part A in the middle;

[0039] Figure 3 for Figure 1 Enlarged view of part B;

[0040] Figure 4 for Figure 1 Enlarged view of part C in the middle;

[0041] Figure 5 It is a schematic diagram of the structure of the negative pressure drainage device;

[0042] Figure 6 It is a vertical cross-sectional view of the negative pressure drainage device;

[0043] Figure 7 This is a schematic diagram of the connection of the negative pressure drainage device.

[0044] In the figure: 1. pressure-resistant shell; 2. water filter infiltration net; 3. drain pipe; 4. seal; 5. siphon pipe joint; 6. annular partition; 7. annular inner cavity; 8. middle inner cavity; 9. water collecting cavity; 10. siphon drain pipe; 11. drain pump; 12. first drain pipe; 13. second drain pipe; 14. pile carrier; 15. high-pressure air pump; 16. pressurized air inlet pipe; 17. drainage well; 18. vacuum negative pressure drainage device; 19. pressurized air injection device; 1901. pressure-resistant and breathable shell; 1902. baffle; 1903. device air inlet pipe; 20. main siphon drain pipe; 21. sealing membrane. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] The application principle of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0047] Example 1

[0048] like Figure 1-7As shown: a vacuum negative pressure drainage system for a soft soil foundation, comprising a drainage well 17, a vacuum negative pressure drainage device 18 and a pressurized gas injection device 19, wherein the vacuum negative pressure drainage device 18 and the pressurized gas injection device 19 are arranged alternately in the soft soil base in the horizontal direction, and a siphon pipe joint 5, a drainage port and a siphon pipe drainage joint are arranged on the surface of the vacuum negative pressure drainage device 18, wherein the drainage port is connected to a drainage pipe 3, wherein the drainage pipe 3 is connected to a second drainage pipe 13, wherein the second drainage pipe 13 connects and collects a plurality of the drainage pipes 3 together through a joint and connects to the drainage well 17, wherein the siphon pipe drainage joint is connected to a siphon drainage pipe 10, wherein the siphon drainage pipe 10 is connected to a main siphon drainage pipe 20, wherein the main siphon drainage pipe 20 connects and collects a plurality of the siphon drainage pipes 10 together through a joint and connects to the drainage well 17, and wherein the outlet end of the main siphon drainage pipe 20 extends below the water surface of the drainage well 17;

[0049] The vacuum negative pressure drainage device 18 is provided with an air inlet on its surface, and the air inlet is connected to a pressurized air inlet pipe 16, and the pressurized air inlet pipe 16 is connected to a high-pressure air pump 15;

[0050] The drainage well 17 is equipped with a first drainage pipe 12 , and the first drainage pipe 12 is connected to a drainage pump 11 .

[0051] The vacuum negative pressure drainage device 18 includes a pressure-resistant shell 1, the surface of the upper half of the pressure-resistant shell 1 is surrounded by a water filtration and infiltration net 2, an annular partition 6 is installed inside the pressure-resistant shell 1, an annular inner cavity 7 is arranged between the pressure-resistant shell 1 and the annular partition 6, an intermediate inner cavity 8 is arranged inside the annular partition 6, a water collecting cavity 9 is arranged below the annular partition 6, the water collecting cavity 9 connects the intermediate inner cavity 8 and the annular inner cavity 7, the drainage pipe 3 extends into the pressure-resistant shell 1 until the insertion end reaches the water collecting cavity 9, the drainage port and the siphon pipe joint 5 are located at the top of the pressure-resistant shell 1, the siphon pipe drainage joint is located at the bottom of the pressure-resistant shell 1, and the siphon pipe drainage joint, the siphon pipe joint 5 and the annular inner cavity 7 are connected.

[0052] The pressurized air injection device 19 includes a pressure-resistant and breathable shell 1901, and air holes are evenly arranged on the surface of the pressure-resistant and breathable shell 1901. Baffles 1902 are arranged inside the pressure-resistant and breathable shell 1901, and the baffles 1902 are arranged in a staggered manner. A device air intake pipe 1903 is installed inside the pressure-resistant and breathable shell 1901, and the device air intake pipe 1903 is connected to the pressurized air intake pipe 16.

[0053] A water pump is installed in the middle inner cavity 8 , a pipe connected to the water inlet of the water pump extends into the water collecting cavity 9 , and a water outlet of the water pump is connected to the drain pipe 3 .

[0054] The plurality of vacuum negative pressure drainage devices 18 are connected end to end to form a multi-layer interconnected structure, and the siphon drainage pipe 10 connects the siphon drainage joints and the siphon joints 5 on the surfaces of the adjacent vacuum negative pressure drainage devices 18 .

[0055] The siphon pipe drainage joint, the siphon pipe joint 5, the drainage port and the pipe connection are all provided with a sealing member 4.

[0056] The surface of the soft soil base layer is covered with a sealing film 21 , and a pile carrier 14 is arranged above the sealing film 21 .

[0057] A film pressing trench is dug around the soft soil foundation, and the film edge of the sealing film 21 is pressed into the film pressing trench, and then the film pressing trench is backfilled.

[0058] The vacuum negative pressure drainage device 18 and the pressurized gas injection device 19 are cylindrical in shape, and a liquid level sensor is arranged inside the vacuum negative pressure drainage device 18 .

[0059] Example 2

[0060] A construction method for a vacuum negative pressure drainage system for a soft soil foundation comprises the following steps:

[0061] S1: The soft soil foundation site is pre-leveled before construction, and cement soil mixing piles or steel sheet piles are used as sealing curtains around to ensure the sealing effect of the soft soil solidification treatment area;

[0062] S2: Arrange measuring points in the soft soil solidification treatment area, arrange settlement points on the side of the soft soil area, and use a one-hole multi-point burial method to lay out layered settlement meters and pore water pressure gauges, and lay out deep horizontal displacement inclinometers at a position of 1.5m from the center point of the side;

[0063] S3: Staggered drilling holes in the soft soil layer, and determining the number of vacuum negative pressure drainage devices 18 and pressurized gas injection devices 19 to be arranged according to the size of the soft soil area. Before placing the vacuum negative pressure drainage devices 18 and the pressurized gas injection devices 19 into the soft soil layer, wrap the outer side of the vacuum negative pressure drainage devices 18 and the pressurized gas injection devices 19 with a water-permeable membrane, and after completion, place the vacuum negative pressure drainage devices 18 and the pressurized gas injection devices 19 into the soft soil layer;

[0064] X1: When the depth of the soft soil layer is shallow, a single layer of the vacuum negative pressure drainage device 18 is set in the soft soil layer, and a main siphon drainage pipe 20 is pre-buried under the vacuum negative pressure drainage device 18 and the siphon drainage pipe 10 is used to connect the siphon drainage port and the main siphon drainage pipe 20;

[0065] X2: When the soft soil layer is deep, the vacuum negative pressure drainage device 18 is connected end to end to set up multiple layers. When connecting, the siphon pipe joints 5 and siphon drainage outlets on the surfaces of adjacent vacuum negative pressure drainage devices 18 are connected through the siphon drainage pipe 10, and a pre-total siphon drainage pipe 20 is excavated deep in the soft soil layer;

[0066] S4: A drainage well 17 is excavated next to the soft soil solidification treatment area, and the main siphon drainage pipe 20 is connected to the siphon drainage pipe 10 through a joint and discharged into the drainage well. At the same time, the booster air intake pipe 16 is connected to the air inlet of the booster air injection device 19 and connected to the device air intake pipe 1903;

[0067] S5: a pressurized gas injection device 19 is arranged in the middle of the vacuum negative pressure drainage device 18;

[0068] S6: Connect the second drain pipe 13 to each drain pipe 3 through a joint, and extend the output end of the second drain pipe 13 into the drain well 17, install the first drain pipe 12 in the drain well 17, and connect the first drain pipe 12 to the drain pump 11, and connect the boost intake pipe 16 to the high-pressure air pump.

[0069] Example 3

[0070] like Figure 1-7 As shown: after the construction and installation of the vacuum negative pressure drainage system for the soft soil foundation is completed, the high-pressure air pump 15 is started, and the high-pressure air is transmitted to the inside of the pressurized air injection device 19 through the pressurized air intake pipe 16, so that the internal pressure of the pressurized air injection device 19 is greater than the pressure of the external soft soil layer, and the high-pressure compressed air enters the gaps in the soft soil layer through the vents evenly arranged on the surface of the pressure-resistant and breathable shell 1901 and squeezes the gap water, so that the gap water moves in the direction away from the pressurized air injection device 19;

[0071] Since the booster gas injection device 19 and the vacuum negative pressure drainage device 18 are arranged alternately, after the booster gas injection device 19 is started, the pressure in the soft soil layer is greater than the pressure inside the vacuum negative pressure drainage device 18. Under the action of the pressure difference, the gap water penetrates the water filtration permeation net 2 into the annular inner cavity 7, and finally collects in the water collection cavity 9 at the bottom of the vacuum negative pressure drainage device 18. The annular inner cavity 7 and the middle inner cavity 8 are connected through the water collection cavity 9 to form a communicating vessel. At the same time, the vacuum negative pressure drainage device 18 is placed underground, and the inside of the device is in a sealed state.

[0072] When the water content in the soft soil layer is low, the water level in the water collection chamber 9 continues to rise and reaches the siphon drainage port. Under the action of gravity, the water flows along the siphon drainage port into the siphon drainage pipe 10. When the vacuum negative pressure drainage device 18 is arranged in a single layer, the siphon drainage pipe 10 and the main siphon drainage pipe 2010 are connected and merged into the drainage well 17.

[0073] When the water content in the soft soil layer is high, the diameter of the siphon drainage pipe 10 is thinner, the drainage speed is slower, and the water level continues to rise, the air in the middle inner cavity 8 is continuously compressed, and when the air pressure in the middle inner cavity 8 is greater than the external atmospheric pressure to form a pressure difference, the water in the water collection chamber 9 will spontaneously flow outward through the drainage pipe 3 and be discharged until the air pressure in the middle inner cavity 8 is equal to the external atmospheric pressure. Due to the effect of the water in the bottom water collection chamber 9, a sealing effect will be continuously produced to ensure that the entire vacuum negative pressure drainage device 18 continues to exist in a vacuum negative pressure environment. At the same time, due to the siphon connection effect, the vacuum negative pressure is ensured to increase continuously, and the processing speed of the vacuum negative pressure drainage device 18 is accelerated. When the water level rises again and causes the air pressure in the middle inner cavity 8 to be greater than the external atmospheric pressure to form a pressure difference, the drainage process is repeated;

[0074] When the water content in the soft soil layer is high and the soft soil layer is deep, the vacuum negative pressure drainage device 18 is connected to multiple layers for use. The siphon drain port of the vacuum negative pressure drainage device 18 of the upper layer is connected to the siphon pipe joint 5 of the vacuum negative pressure drainage device 18 of the lower layer, and the siphon drain port of the vacuum negative pressure drainage device 18 of the bottom layer is connected to the main siphon drain pipe 2010. When the booster gas injection device 19 is started, the water in the water collection chamber 9 inside the vacuum negative pressure drainage device 18 of the upper layer will be transported to the inside of the vacuum negative pressure drainage device of the lower layer through the siphon drain pipe 10 under the action of gravity until it is transmitted to the vacuum negative pressure drainage device of the bottom layer. In 18, since the most vacuum negative pressure drainage device 18 is not only subjected to the pressure generated by the pressurized gas injection device 19, but also the gravity of the soil layer and the ballast body, the internal and external pressure difference of the vacuum negative pressure drainage device 18 of the lowest layer is relatively large, and at the same time, it also needs to receive the water flow out of the vacuum negative pressure drainage device 18 of the upper layer, so that the water flow inside the vacuum negative pressure drainage device 18 of the lowest layer rises very quickly. At this time, the efficiency of autonomous drainage relying solely on the pressure difference is low. The staff can install a water pump inside the vacuum negative pressure drainage device 18 of the lowest layer. When the water level exceeds a certain limit, the liquid level sensor is triggered and the water pump is started to improve the drainage efficiency.

[0075] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0076] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A vacuum negative pressure drainage system for soft soil foundation, characterized by: It comprises a drainage well (17), a vacuum negative pressure drainage device (18) and a pressurized gas injection device (19); the surface of the vacuum negative pressure drainage device (18) is provided with a siphon pipe joint (5), a drainage port and a siphon pipe drainage joint; the drainage port is connected to a drainage pipe (3); the drainage pipe (3) is connected to a second drainage pipe (13); the second drainage pipe (13) is connected to a plurality of the drainage pipes (3); the second drainage pipe (13) is connected to the drainage well (17); the siphon pipe drainage joint is connected to a siphon drainage pipe (10); the siphon drainage pipe (10) is connected to a main siphon drainage pipe (20); the main siphon drainage pipe (20) is connected to a plurality of the siphon drainage pipes (10); the main siphon drainage pipe (20) is connected to the drainage well (17); The vacuum negative pressure drainage device (18) is provided with an air inlet on its surface, the air inlet is connected to a pressurized air inlet pipe (16), and the pressurized air inlet pipe (16) is connected to a high-pressure air pump (15); The drainage well (17) is equipped with a first drainage pipe (12), and the first drainage pipe (12) is connected to a drainage pump (11).

2. A vacuum negative pressure drainage system for soft soil foundation according to claim 1, characterized in that: The vacuum negative pressure drainage device (18) comprises a pressure-resistant shell (1), the surface of the upper half of the pressure-resistant shell (1) is surrounded by a water filter infiltration net (2), an annular partition (6) is installed inside the pressure-resistant shell (1), an annular inner cavity (7) is formed between the pressure-resistant shell (1) and the annular partition (6), the annular partition (6) includes an intermediate inner cavity (8), a water collecting cavity (9) is formed below the annular partition (6), the water collecting cavity (9) connects the intermediate inner cavity (8) and the annular inner cavity (7), and the drainage pipe (3) extends into the pressure-resistant shell (1) until the insertion end reaches the water collecting cavity (9).

3. The vacuum negative pressure drainage system for soft soil foundation according to claim 1, characterized in that: The pressurized air injection device (19) comprises a pressure-resistant air-permeable shell (1901), the surface of the pressure-resistant air-permeable shell (1901) is evenly provided with air holes, a baffle (1902) is arranged inside the pressure-resistant air-permeable shell (1901), the baffles (1902) are arranged in a staggered manner, and a device air intake pipe (1903) is installed inside the pressure-resistant air-permeable shell (1901), and the device air intake pipe (1903) is connected to the pressurized air intake pipe (16).

4. The vacuum negative pressure drainage system for soft soil foundation according to claim 2, characterized in that: The drain port and the siphon pipe joint (5) are located at the top of the pressure-resistant shell (1), the siphon pipe drain joint is located at the bottom of the pressure-resistant shell (1), and the siphon pipe drain joint, the siphon pipe joint (5) and the annular inner cavity (7) are connected; When the vacuum negative pressure drainage device (18) is arranged in a single layer, the siphon pipe joint (5) is closed, and the siphon pipe drainage joint is connected to the main siphon drainage pipe (20) via the siphon drainage pipe (10); When the vacuum negative pressure drainage devices (18) are arranged in staggered layers, the adjacent vacuum negative pressure drainage devices (18) on the upper and lower layers are connected via a siphon drainage pipe (10), the siphon pipe joint (5) of the vacuum negative pressure drainage device (18) on the top layer is closed, and the siphon drainage joint of the vacuum negative pressure drainage device (18) on the bottom layer is connected to the main siphon drainage pipe (20) via the siphon drainage pipe (10).

5. The vacuum negative pressure drainage system for soft soil foundation according to claim 2, characterized in that: A water pump is installed in the middle inner cavity (8); a pipe connected to a water inlet of the water pump extends into the water collecting cavity (9); and a water outlet of the water pump is connected to a drain pipe (3).

6. The vacuum negative pressure drainage system for soft soil foundation according to claim 2, characterized in that: The plurality of vacuum negative pressure drainage devices (18) form a interconnected structure of at least two layers in soil layers at different depths, and the siphon drainage pipe (10) connects the siphon drainage joints and the siphon joints (5) on the surfaces of adjacent vacuum negative pressure drainage devices (18).

7. The vacuum negative pressure drainage system for soft soil foundation according to claim 2, characterized in that: The siphon pipe drainage joint, the siphon pipe joint (5), the drainage port and the pipe connection are all provided with sealing members (4).

8. The vacuum negative pressure drainage system for soft soil foundation according to claim 1, characterized in that: The surface of the soft soil base layer is covered with a sealing film (21), a pile carrier (14) is arranged above the sealing film (21), and a film pressing groove is dug around the soft soil base. The edge of the sealing film (21) is pressed into the film pressing groove, and then the film pressing groove is backfilled.

9. The vacuum negative pressure drainage system for soft soil foundation according to claim 1, characterized in that: The vacuum negative pressure drainage device (18) and the pressurized gas injection device (19) are cylindrical in shape, and a liquid level sensor is arranged inside the vacuum negative pressure drainage device (18).

10. A construction method of a vacuum negative pressure drainage system for a soft soil foundation, comprising the vacuum negative pressure drainage system for a soft soil foundation according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: The soft soil foundation site is pre-leveled before construction, and cement soil mixing piles or steel sheet piles are used as sealing curtains around to ensure the sealing effect of the soft soil solidification treatment area; S2: Arrange measuring points in the soft soil solidification treatment area, arrange settlement points on the side of the soft soil area, and use a one-hole multi-point burial method to lay out layered settlement meters and pore water pressure gauges, and lay out deep horizontal displacement inclinometers at a position of 1.5m from the center point of the side; S3: Staggered drilling holes are made in the soft soil layer, and the number of vacuum negative pressure drainage devices (18) and pressurized gas injection devices (19) is determined according to the size of the soft soil area. Before the vacuum negative pressure drainage devices (18) and the pressurized gas injection devices (19) are placed in the soft soil layer, a water-permeable membrane is wrapped around the outside of the vacuum negative pressure drainage devices (18) and the pressurized gas injection devices (19). After completion, the vacuum negative pressure drainage devices (18) and the pressurized gas injection devices (19) are placed in the soft soil layer; X1: When the depth of the soft soil layer is relatively shallow, a single layer of the vacuum negative pressure drainage device (18) is arranged in the soft soil layer, and a main siphon drainage pipe (20) is pre-buried under the vacuum negative pressure drainage device (18), and the siphon drainage pipe (10) is used to connect the siphon drainage port and the main siphon drainage pipe (20); X2: When the soft soil layer is deep, the vacuum negative pressure drainage device (18) is arranged in multiple layers in soil layers of different depths. When connecting, the siphon pipe joints (5) and siphon drainage outlets on the surfaces of adjacent vacuum negative pressure drainage devices (18) are connected through the siphon drainage pipe (10), and a pre-total siphon drainage pipe (20) is excavated deep in the soft soil layer; S4: A drainage well (17) is excavated next to the soft soil solidification treatment area, and the main siphon drainage pipe (20) is connected to the siphon drainage pipe (10) through a joint and discharged into the drainage well. At the same time, the booster air intake pipe (16) is connected to the air inlet of the booster air injection device (19) and connected to the device air intake pipe (1903); S5: arranging a pressurized gas injection device (19) in the middle of the vacuum negative pressure drainage device (18); S6: Connect the second drainage pipe (13) to each drainage pipe (3) via a joint, and extend the output end of the second drainage pipe (13) into the drainage well (17), install the first drainage pipe (12) in the drainage well (17), and connect the first drainage pipe (12) to the drainage pump (11), and connect the boost intake pipe (16) to the high-pressure air pump.

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