Pressurized forward and reverse vacuum preloading soft soil foundation treatment method

Abstract

The invention discloses a supercharged forward and reverse vacuum preloading soft soil foundation treatment method which comprises the following steps that S1, a plurality of forward drainage plates and reverse drainage plates are inserted in a soft soil foundation at intervals, the forward drainage plates and the reverse drainage plates are distributed at intervals, and sealing joints are arranged at the two ends of the forward drainage plates and the two ends of the reverse drainage plates; s2, a top end connector of the forward drainage plate is connected with an external vacuum pump through a forward drainage main pipe and connected with an external supercharging device through a ventilation pipeline; s3, a bottom connector of the reverse drainage plate is connected with an external vacuum pump through a reverse drainage main pipe and connected with an external supercharging device through a reverse gas filling branch pipe and a ventilation pipeline; s4, an external vacuum pump starts to work, and the forward drainage plate and the reverse drainage plate conduct pumping drainage at the same time; and S5, the vacuum pump and the supercharging device work alternately till the soft soil foundation is settled to the designated depth. According to the method, the drainage efficiency of the soft soil foundation is improved, and the good consolidation effect on the soil body is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of soft soil foundation reinforcement, in particular to a pressurized positive and negative vacuum preloading soft soil foundation treatment method. Background Art

[0002] Soft soil foundation has many unfavorable engineering properties such as high water content, high compressibility, low shear strength, etc. High compressibility will lead to considerable settlement and settlement difference of the foundation, low permeability will make the settlement last for a long time, which may affect the normal use of the building, and low strength will make the bearing capacity and stability of the foundation often fail to meet the engineering requirements. Therefore, how to effectively, quickly and economically strengthen such ultra-soft foundation has become a technical problem that must be solved.

[0003] After decades of practical application in engineering, the vacuum preloading method has formed a mature construction process and design method. The vacuum preloading method uses a vacuum pump to form a negative pressure in the soil by vacuuming, so that the moisture in the soil is discharged along the drainage board, thereby achieving the purpose of consolidating the soil. However, during the vacuum preloading process, the negative pressure formed is often difficult to transmit to the deep soil, resulting in poor drainage and consolidation effects on deep soft soil foundations. Summary of the invention

[0004] In view of the shortcomings of the background technology, the technical problem to be solved by the present invention is to provide a pressurized positive and negative vacuum preloading soft soil foundation treatment method, which avoids clogging of drainage plates, improves the drainage efficiency of deep soft soil foundations, and has a good consolidation effect on the soil.

[0005] The present invention is completed by adopting the following technical scheme: a pressurized forward and reverse vacuum preloading soft soil foundation treatment method, comprising the following steps:

[0006] S1. Multiple forward drain boards and reverse drain boards are inserted into the soft soil foundation at intervals, and the forward drain boards and reverse drain boards are distributed at intervals, and both ends of the forward drain boards and reverse drain boards have sealing joints;

[0007] S2. The top joint of the forward drainage plate is connected to the external vacuum pump through the forward drainage main pipe, and is connected to the external booster device through the ventilation pipe;

[0008] S3. The bottom joint of the reverse drainage plate is connected to the external vacuum pump through the reverse drainage main pipe, and is connected to the external pressurizing device through the reverse gas branch pipe through the ventilation pipe;

[0009] S4. Geotextile is laid on the upper surface of the soft soil foundation, and the external vacuum pump starts to work. The forward drainage board and the reverse drainage board are pumped out at the same time. After a period of pumping, the vacuum pump is turned off, and the booster device is turned on to flush gas through the ventilation pipe, the gas branch pipe and the drainage board pipeline;

[0010] S5. The vacuum pump and the booster device work alternately until the soft soil foundation settles to the specified depth.

[0011] Effects of the present invention:

[0012] 1. The vacuum pump and the booster device work alternately, and vacuuming and boosting are performed alternately. During the vacuum drainage process, sludge is caused to block the drain board. The booster device is used to add air to remove the sludge on the drain board, avoid clogging the drain board, and improve the drainage efficiency;

[0013] 2. The use of positive and negative drainage boards at intervals solves the problem of poor drainage effect of the drainage board on deep soft soil foundation. The positive drainage board and the reverse drainage board work at the same time, and the shallow soft soil foundation and the deep soft soil foundation are drained at the same time, which improves the drainage efficiency and improves the overall consolidation effect of the soft soil foundation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention has the following accompanying drawings:

[0015] Figure 1 It is a structural schematic diagram of a first embodiment of a pressurized forward and reverse vacuum preloading soft soil foundation treatment method after construction;

[0016] Figure 2 It is a structural schematic diagram of a forward drainage board of a second embodiment of a pressurized forward and reverse vacuum preloading soft soil foundation treatment method;

[0017] Figure 3 It is a structural schematic diagram of a reverse drainage board of a second embodiment of a pressurized forward and reverse vacuum preloading soft soil foundation treatment method;

[0018] Figure 4 for Figure 2 Schematic diagram of the transverse cross-section structure of the central drainage board;

[0019] Figure 5 for Figure 2 Schematic diagram of the partial structure of the middle drainage board pipeline. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Reference Figure 1 As shown, the first embodiment of the present invention provides a method for treating soft soil foundation by positive and negative vacuum preloading, comprising the following steps:

[0022] S1. Multiple forward drain boards 1 and reverse drain boards 2 are inserted at intervals in the soft soil foundation. The forward drain boards 1 and reverse drain boards 2 are spaced apart, and sealing joints are provided at both ends of the forward drain boards and reverse drain boards. Wherein, both sides of the forward drain boards and reverse drain boards have multiple drainage channels 3, and the drainage channels on both sides are symmetrically arranged back to back, and the number of drainage channels on both sides is consistent.

[0023] S2. The top joint 5 of the forward drainage plate is connected to the external vacuum pump 8 through the forward drainage main pipe 7, and is connected to the external booster device 10 through the ventilation pipe 9.

[0024] Specifically, the top joint 5 of the forward drainage plate has a forward gas-filling branch pipe 11 and a forward drainage branch pipe 12. The forward drainage branch pipe 12 is connected to the forward drainage main pipe 7. The forward drainage main pipe 7 is connected to the external vacuum pump 8 through a pipeline 13. The forward gas-filling branch pipe is connected to the external booster device through a ventilation pipe.

[0025] S3. The bottom joint 6 of the reverse drainage plate is connected to the external vacuum pump 8 through the reverse drainage main pipe 14, and is connected to the external booster device 10 through the reverse air supply branch pipe 15 and the ventilation pipe 16.

[0026] Specifically, the bottom joint 6 of the reverse drainage plate has a reverse air supply branch pipe 15 and a reverse drainage branch pipe 18. The reverse drainage branch pipe 18 is connected to the reverse drainage main pipe 14. The reverse drainage main pipe 14 is connected to the external vacuum pump 8 through the pipeline 19. The reverse air supply branch pipe 15 is connected to the external boosting device 10 through the ventilation pipe 16.

[0027] S4. Geotextile 17 is laid on the upper surface of the soft soil foundation, and the external vacuum pump 8 starts to work. The forward drain board 1 and the reverse drain board 2 are pumped at the same time. After a period of pumping, the vacuum pump 8 is turned off, and the booster device 10 is turned on. The forward drain board is flushed with gas through the ventilation pipe 9, the forward gas branch pipe 11 and the drain board pipeline 4, and the reverse drain board is flushed with gas through the ventilation pipe 16, the reverse gas branch pipe 15 and the drain board pipeline 4 to remove the silt at the drain board and prevent the drain board from clogging. Preferably, the gas pressure of the booster device is preferably 20 kPa, and the boosting time is preferably 2 hours per day.

[0028] S5. The vacuum pump 8 and the booster device 10 work alternately until the soft soil foundation settles to the specified depth. The vacuum pump and the booster device work alternately, and vacuuming and boosting are performed alternately. During the vacuum drainage process, silt blocks the drain board. The booster device is used to add air to remove the silt at the drain board, avoid clogging the drain board, and improve the drainage efficiency.

[0029] The positive and negative drainage boards are set at intervals. The positive drainage boards are used to drain and consolidate the shallow soft soil foundation, while the negative drainage boards are used to drain and consolidate the deep soft soil foundation. The positive and negative drainage boards work at the same time, and the shallow and deep soft soil foundations are drained at the same time, which improves the drainage efficiency and the overall consolidation effect of the soft soil foundation.

[0030] Reference Figure 2-5 The second embodiment of the present invention provides a pressurized forward and reverse vacuum preloading soft soil foundation treatment method. The above-mentioned pressurized forward and reverse vacuum preloading soft soil foundation treatment method is basically the same as the first embodiment, except that: in step S1, the drainage passage of the forward drain board or the reverse drain board is inserted with a drainage board pipeline system 4, and one end of the drainage board pipeline system is connected to one of the joints. Specifically, the top of the pipeline in the forward drain board is connected to the top joint 5 of the forward drain pipe, and the bottom of the pipeline in the reverse drain pipe is connected to the bottom joint 6 of the reverse drain pipe.

[0031] The drainage board pipeline system 4 is composed of a plurality of pipelines of different lengths, each of which is inserted into the drainage passage 3 of a different drainage board, and the pipelines are arranged in a stepped manner. Specifically, the pipelines in the passage on one side of the drainage board are arranged in a stepped manner from short to long, and the symmetrical passages on the other side are arranged in a stepped manner from long to short (i.e., the drainage passage corresponding to the shortest pipeline 41 is set to the longest pipeline 42 back to back). The top of the pipeline in the forward drainage board is connected to the top joint 5 of the forward drainage pipe, and the bottom of the pipeline in the reverse drainage pipe is connected to the bottom joint 6 of the reverse drainage pipe.

[0032] Each of the pipelines is a hollow pipeline, and a number of tube holes 43 are evenly arranged on the side wall of each pipeline. A number of tube holes are evenly arranged on the shortest pipeline. The tube holes 43 of the other pipelines except the shortest pipeline are distributed at the lower end of the pipeline, and the highest end tube hole of the longer pipeline among the adjacent pipelines is flush with the bottom end of the shorter pipeline. A convex edge 44 is arranged on the outer side wall of the bottom end of each pipeline. During the vacuuming process, the convex edge 44 of the pipeline and the bottom limits the deformation range of the drain board, reduces the deformation degree of the drain board, and improves the deformation resistance of the drain board. The convex edge 44 at the bottom of the pipeline limits the distance between the filter membrane 20 wrapped inside the drain board and outside the drain board, preventing the filter membrane 20 outside the drain board from sticking to each other and blocking the drainage passage, thereby avoiding obstruction of the drainage passage.

[0033] The forward drain plate and the reverse drain plate are inserted in the soft soil base at intervals, that is, the shortest pipeline 41 in the forward drain plate corresponds to the longest pipeline 42 of its adjacent reverse drain plate. When the vacuum pump is turned on, the forward drain plate and the reverse drain plate are vacuumed and drained through the bottom holes and side wall holes of the pipelines in turn. The stepped pipelines are vacuumed for soft soil bases of different depths, which improves the drainage efficiency and the consolidation effect.

[0034] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for treating soft soil foundation by positive and negative vacuum preloading, characterized by: The following steps are included: S1. Multiple forward drain boards and reverse drain boards are inserted into the soft soil foundation at intervals, and the forward drain boards and reverse drain boards are distributed at intervals, and both ends of the forward drain boards and reverse drain boards have sealing joints; S2. The top joint of the forward drainage plate is connected to the external vacuum pump through the forward drainage main pipe, and is connected to the external booster device through the ventilation pipe; S3. The bottom joint of the reverse drainage plate is connected to the external vacuum pump through the reverse drainage main pipe, and is connected to the external pressurizing device through the reverse gas branch pipe through the ventilation pipe; S4. The external vacuum pump starts working, and the forward drain board and the reverse drain board are pumped out at the same time. After a period of pumping, the vacuum pump is turned off, and the booster device is turned on to flush gas through the ventilation pipe, the gas branch pipe and the drain board pipeline; S5. The vacuum pump and the booster device work alternately until the soft soil foundation settles to the specified depth.

2. The method for treating soft soil foundation by using a boosted positive and negative vacuum preloading method according to claim 1 is characterized by: The top joint of the forward drainage plate has a forward gas branch pipe and a forward drainage branch pipe, the forward drainage branch pipe is connected to the forward drainage main pipe, the forward drainage main pipe is connected to an external vacuum pump through a pipeline, and the forward gas branch pipe is connected to an external booster device through a ventilation pipe.

3. A method for treating soft soil foundation by positive and negative vacuum preloading according to claim 2, characterized in that: The bottom joint of the drain plate has a reverse gas branch and a reverse drainage branch. The reverse drainage branch is connected to the reverse drainage main pipe. The reverse drainage main pipe is connected to an external vacuum pump through a pipeline. The reverse gas branch is connected to an external pressurizing device through a ventilation pipe.

4. A method for treating soft soil foundation by using a boosted positive and negative vacuum preloading method according to claim 1, 2 or 3, characterized in that: A drainage board pipeline system is inserted in the forward drainage board or the reverse drainage board. Both ends of the forward drainage board and the reverse drainage board are provided with sealing joints, and one end of the drainage board pipeline system is connected to one of the joints.

5. According to the pressurized forward and reverse vacuum preloading soft soil foundation treatment method described in claim 4, the drainage board pipeline system is composed of a plurality of pipelines of different lengths, each pipeline is inserted into the drainage passage of a different drainage board, and the pipelines are arranged in a stepped manner. The top of the pipeline in the forward drainage board is conductively connected to the top joint of the forward drainage pipe, and the bottom of the pipeline in the reverse drainage pipe is conductively connected to the bottom joint of the reverse drainage pipe.

6. The method for treating soft soil foundation by positive and negative vacuum preloading according to claim 5 is characterized by: Each pipeline side wall is evenly provided with a number of pipe holes. Except for the shortest pipeline, the pipe holes of other pipelines are distributed at the lower end of the pipeline. The highest end pipe hole of the longer pipeline among adjacent pipelines is flush with the lower end of the shorter pipeline.

7. A method for treating soft soil foundation by using a boosted positive and negative vacuum preloading method according to claim 5 or 6, characterized in that: The drainage board has drainage passages on both sides, which are symmetrically arranged. The pipelines in the passages on one side of the drainage board are arranged in a step-like manner from short to long, and the symmetrical passages on the other side of the drainage board are arranged in a step-like manner from long to short.

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