Soft soil consolidated preloading soft foundation treatment structure and construction method thereof

Abstract

The invention relates to a soft soil consolidation preloading soft foundation treatment structure and a construction method thereof.The preloading preloading soft foundation treatment structure is used for being arranged in a soft soil foundation area below the earth surface, the bottom of the soft soil foundation area is a soft foundation soil bottom layer, and the soft foundation soil bottom layer comprises a sand cushion layer, at least two sand pile filling layers and at least two soft foundation soil layers; the number of the sand pile filling layers is consistent with that of the soft foundation soil layers; the sand pile filling layers and the soft foundation soil layers are sequentially and alternately arranged on the soft foundation soil bottom layer in the vertical direction, the sand pile filling layers form a transverse first drainage face between the soft foundation soil bottom layer and the soft foundation soil layers, and the sand pile filling layers form a transverse second drainage face between the soft foundation soil layers. Forming a soft foundation structure with at least two drainage surfaces; and the sand cushion layer is arranged on the soft foundation structure. According to the soft foundation structure, at least two sand pile filling layers are arranged, at least two transverse drainage faces are formed in the soft foundation structure, and compared with single-face drainage, multi-face drainage can improve the drainage efficiency and accelerate the soft soil consolidation speed.

Description

Technical Field

[0001] The present invention relates to the technical field of foundation treatment construction, and in particular to a soft soil consolidation preloading soft foundation treatment structure and a construction method thereof. Background Art

[0002] Soft soil foundation has the remarkable characteristics of high compressibility and low strength. If municipal road construction is carried out directly on such soft soil foundation, it is often difficult to meet the strict requirements of post-construction settlement. Therefore, corresponding reinforcement measures must be taken for the soft soil foundation to meet the needs of subsequent engineering construction. In many engineering practices, the preloading method is a traditional, time-tested and effective method for reinforcing soft soil foundation.

[0003] After searching, it is known that in the prior art, for example, patent CN201810303338.2 discloses a preloading soft foundation treatment structure and method, in which a sand cushion layer is laid on the foundation to be loaded, and a cofferdam is provided on the ground around the sand cushion layer, and the area of ​​the preloading treatment range of the foundation to be loaded is enclosed by the cofferdam to form a cofferdam pit; a waterproof sealing membrane is laid along the inner surface of the cofferdam pit and the surface of the sand cushion layer to form a water storage structure, and a number of pumping structures for injecting water into the cofferdam pit are installed on the cofferdam. The cofferdam water injection and loading method is adopted, and water is first injected for loading. After meeting the unloading requirements, the water inside the cofferdam is pumped out with a water pump, and the plastic cushion layer is removed. The earth cofferdam is used as earth and stone to compensate for foundation settlement, and backfill and compaction are carried out, and then the remaining earth and stone are discarded. The above-mentioned preloading soft foundation treatment structure and method still have the following disadvantages in practical applications:

[0004] Firstly, the preloading soft foundation treatment structure mainly relies on the drainage board or vertical drainage manhole inserted under the sand cushion layer as the vertical drainage channel. The drainage path is relatively simple and belongs to the single-sided drainage form. When treating the soft soil foundation with the same thickness, the drainage efficiency of the single-sided drainage form is relatively low; and it relies on the pumping structure installed on the cofferdam to inject water into the cofferdam pit to form a certain water pressure difference to promote the drainage of the soft foundation. The water pressure difference formed by the water injection is relatively difficult to accurately control and maintain stability. Once the pumping structure fails or the water injection situation does not meet expectations, the drainage power will be significantly affected, which will make the pore water discharge process in the soft foundation unstable, and intermittent drainage may occur, affecting the uniformity and timeliness of the soft soil consolidation.

[0005] Secondly, in the water injection and loading stage of the soft foundation treatment structure method, it is not easy to accurately control the water level in the cofferdam to achieve appropriate load application. If the water level is too high, the soft soil foundation may be subjected to excessive load in a short period of time, exceeding its bearing capacity, causing local shear failure of the soft foundation and affecting the subsequent consolidation effect of the entire soft foundation; if the water level is too low, the expected loading pressure cannot be achieved, and the pore water cannot be effectively driven out. The consolidation process of the soft soil is slow, making it difficult to meet the unloading requirements and prolonging the treatment cycle. Summary of the invention

[0006] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present disclosure is to provide a soft soil consolidation preloading soft foundation treatment structure and a construction method thereof. The soft soil consolidation preloading soft foundation treatment structure forms at least two lateral drainage surfaces in the soft foundation structure by setting at least two layers of sand filling layers. Compared with single-sided drainage, this multi-faceted drainage can significantly improve drainage efficiency, accelerate the consolidation speed of soft soil, shorten the time required to reach the expected consolidation degree, and greatly shorten the construction period of soft foundation treatment.

[0007] The soft soil consolidation preloading soft foundation treatment structure disclosed in the present invention is used to be arranged in a soft soil foundation area below the ground surface, the bottom of the soft soil foundation area is a soft foundation soil bottom layer, including a sand cushion layer, at least two layers of sand pile filling layers and at least two layers of soft foundation soil layers, and the number of layers of the sand pile filling layers and the soft foundation soil layers is the same;

[0008] The sand filling layer and the soft soil layer are alternately arranged on the soft soil bottom layer in the vertical direction, the sand filling layer forms a transverse first drainage surface between the soft soil bottom layer and the soft soil layer, and the sand filling layer forms a transverse second drainage surface between two adjacent soft soil layers, forming a soft foundation structure with at least two drainage surfaces;

[0009] The sand cushion layer is arranged on the soft foundation structure;

[0010] The sand pile filling layer includes a plurality of sand piles arranged in a horizontal direction, and the cross section of the sand pile in a vertical direction is elliptical;

[0011] The soft foundation structure is interspersed with a number of sand wells, which form vertical drainage channels;

[0012] The soft foundation structure has a groove-shaped boundary water collection tank on the four sides, and the boundary water collection tank is provided with a plurality of water pumping pipes along the vertical direction, one end of the water pumping pipe is connected to the water collection tank, and the other end is connected to the water pump;

[0013] A drainage pipe is provided inside the sand cushion layer, and the drainage pipe is arranged in a horizontal direction to form a transverse drainage channel;

[0014] It also includes a geomembrane layer and a loading layer. The geomembrane layer is arranged on a side of the sand cushion layer away from the soft foundation structure, and the loading layer is arranged on a side of the geomembrane layer away from the sand cushion layer.

[0015] Preferably, the two sand filling layers include a first sand filling layer and a second sand filling layer;

[0016] The two soft soil layers include a first soft soil layer and a second soft soil layer.

[0017] A construction method for a soft soil consolidation preloading soft foundation treatment structure is applied to the soft soil consolidation preloading soft foundation treatment structure as described above, and comprises the following steps:

[0018] S1. Fill the soft foundation with sand to form a soft foundation structure;

[0019] S2, construction of bagged sand well;

[0020] S3, digging trenches on the boundaries of the soft foundation structure;

[0021] S4. Lay machine-made sand and pre-bury drainage pipes;

[0022] S5. Laying geomembrane;

[0023] S6. Carry out construction loading in combination with the soft foundation strength

[0024] Preferably, the step S1 specifically includes:

[0025] In the soft soil foundation area below the ground surface, the construction depth is set, and the sand wells are measured and laid out. After drilling with a rotary jet drilling rig, machine-made sand is sprayed between the soft soil bottom layer and the first soft soil layer in the soft soil foundation area to form a first sand pile filling layer. After the construction of the first sand pile filling layer is completed, a sand pile is filled between the first soft soil layer and the second soft soil layer to form a second sand pile filling layer. After the two layers of filled sand piles are completed in sequence, the soft foundation structure with two drainage surfaces is formed.

[0026] Preferably, the step S2 specifically includes:

[0027] After the construction of the filling sand pile is completed, the sand is put into sand bags to form the bagged sand wells, and the bagged sand wells are implanted into the soft foundation structure at intervals along the vertical direction by a plunge drill to form sand wells, and the sand wells form vertical drainage channels inside the soft foundation structure.

[0028] Preferably, a boundary water collection trough is formed by excavating the edges of the soft foundation structure according to the set width and depth using a trenching machine, and a plurality of pumping pipes are arranged in the boundary water collection trough at a certain interval, and the pumping pipes extend in the vertical direction;

[0029] After the pumping pipe is set, fill the boundary sump with manufactured sand to provide a vertical drainage surface for the untreated soft foundation part;

[0030] The water pumping pipe is connected to a water pump, and water is pumped by the water pump to form well point dewatering.

[0031] Preferably, the step S4 specifically includes:

[0032] On one side of the soft foundation structure away from the second soft foundation soil layer, machine-made sand is laid, and a certain thickness is laid in a direction away from the second soft foundation soil layer to form a sand cushion layer;

[0033] A plurality of drainage pipes are buried in the sand cushion layer along the horizontal direction, and the drainage pipes extend transversely to form a transverse drainage channel.

[0034] Preferably, the step S5 specifically includes:

[0035] After the construction of the sand cushion layer is completed, a geomembrane is laid on a side of the sand cushion layer away from the soft foundation structure to form a geomembrane layer.

[0036] Preferably, the step S6 specifically includes:

[0037] In combination with the growth of soft foundation strength, the geomembrane layer is loaded step by step. While the loading is being constructed, all the pumping pipes are connected to the pump to discharge the accumulated water in the boundary sump, so that well point precipitation is generated at the bottom of the boundary sump to form a loading layer.

[0038] The advantages of the soft soil consolidation preloading soft foundation treatment structure and the construction method thereof disclosed in the present invention are:

[0039] 1. A soft soil consolidation preloading soft foundation treatment structure disclosed in the present invention is used to be arranged in a soft soil foundation area below the ground surface, the bottom of the soft soil foundation area is a soft soil bottom layer, including a sand cushion layer, at least two sand pile filling layers and at least two soft soil layers, and the number of sand pile filling layers and the soft soil layers are the same; the sand pile filling layers and the soft soil layers are alternately arranged on the soft soil bottom layer in a vertical direction, the sand pile filling layer forms a first transverse drainage surface between the soft soil bottom layer and the soft soil layer, and the sand pile filling layer forms a second transverse drainage surface between the soft soil layer and the soft soil layer, forming a soft foundation structure with at least two drainage surfaces; the sand cushion layer is arranged on the soft foundation structure. By setting at least two layers of sand filling layers, at least two lateral drainage surfaces are formed in the soft foundation structure. Compared with single-sided drainage, this multi-sided drainage can significantly improve drainage efficiency, accelerate the consolidation speed of soft soil, shorten the time required to reach the expected consolidation degree, greatly shorten the construction period of soft foundation treatment, create a good working surface for subsequent construction and win precious time; and to a certain extent, it solves the problem of limited isolation effect of waterproof sealing membrane on surrounding soil layer groundwater in traditional structures. Through the reasonable drainage system constructed by itself, the water in the soft foundation structure is discharged in an orderly manner along the designed lateral drainage surface and other paths, so that the hydraulic state inside the soft foundation structure is relatively stable, and the resistance to external groundwater is enhanced, which can greatly reduce the occurrence of groundwater from the surrounding soil layer infiltrating into the soft foundation area to destroy the drainage consolidation state.

[0040] 2. The present invention discloses a method for constructing a soft soil consolidation preloading soft foundation treatment structure, which comprises the following steps: S1, filling a sand pile inside the soft foundation to form a soft foundation structure; S2, constructing a bagged sand well; S3, digging a trench at the boundary of the soft foundation structure; S4, laying machine-made sand and pre-burying drainage pipes; S5, laying a geomembrane; S6, constructing a preloading structure based on the strength of the soft foundation. The construction method forms a horizontal drainage surface at different heights of the soft foundation by filling sand piles inside the soft foundation, changing the traditional single drainage path mode, increasing the dimension of drainage and improving efficiency; the construction of bagged sand wells creates a vertical drainage channel, which cooperates with the horizontal drainage surface to form a three-dimensional drainage system. In addition, the laying of machine-made sand and the pre-buried drainage pipes further expand and optimize the entire drainage network, so that the pore water in the soft soil foundation can be quickly discharged through a variety of channels, effectively solving the problems of slow drainage and long consolidation time of the soft soil foundation, accelerating the consolidation speed of soft soil, and shortening the soft foundation treatment period; and this multi-mode combined drainage system does not rely on a single drainage driving mechanism. Compared with relying on only one drainage structure or external unstable factors to promote drainage, it can make the drainage process more stable and reliable based on the characteristics of the soft soil itself and the mutual cooperation between the drainage structures, and it is not easy to cause drainage interruption or poor drainage due to external equipment failure or environmental changes, thereby ensuring the continuity and uniformity of soft soil drainage consolidation. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a vertical cross-sectional view of a soft soil consolidation preloading soft foundation treatment structure disclosed in the present invention;

[0042] Figure 2 It is a horizontal cross-sectional view of a soft soil consolidation preloading soft foundation treatment structure disclosed in the present invention;

[0043] Figure 3 The present invention discloses a flow chart of a method for constructing a soft soil consolidation preloading soft foundation treatment structure.

[0044] Description of reference numerals:

[0045] 10-sand cushion layer;

[0046] 20-sand filling layer;

[0047] 30-soft soil layer;

[0048] 40-Sand well;

[0049] 50-Boundary sump;

[0050] 60-water pump;

[0051] 70-geomembrane layer;

[0052] 80-loading layer. DETAILED DESCRIPTION

[0053] like Figure 1 - Figure 3 As shown, a soft soil consolidation preloading soft foundation treatment structure disclosed in the present invention is used to be arranged in a soft soil foundation area below the ground surface, and the bottom of the soft soil foundation area is a soft foundation soil bottom layer, including a sand cushion layer 10, at least two layers of sand pile filling layers 20 and at least two layers of soft foundation soil layers 30, and the number of layers of the sand pile filling layers 20 and the soft foundation soil layers 30 is the same;

[0054] The sand filling layer 20 and the soft foundation soil layer 30 are alternately arranged on the soft foundation soil bottom layer in the vertical direction, the sand filling layer 20 forms a transverse first drainage surface between the soft foundation soil bottom layer and the soft foundation soil layer 30, and the sand filling layer 20 forms a transverse second drainage surface between two adjacent soft foundation soil layers 30, forming a soft foundation structure with at least two drainage surfaces;

[0055] The sand cushion layer 10 is arranged on the soft foundation structure; the sand cushion layer 10 is formed by laying a certain thickness of machine-made sand on the surface of the soft foundation structure;

[0056] The sand pile filling layer 20 includes a plurality of sand piles arranged in the horizontal direction, and the cross section of the sand pile in the vertical direction is elliptical; the plurality of sand piles are adjacently stacked in the horizontal direction, so that the porosity in the soft soil is increased in the local area;

[0057] The soft foundation structure is interspersed with a plurality of sand wells 40, and the sand wells 40 form a vertical drainage channel; the plurality of sand wells 40 are evenly spaced;

[0058] The soft foundation structure has a groove-shaped boundary water collection tank 50 on the four sides. The boundary water collection tank 50 is provided with a plurality of water pumping pipes 60 along the vertical direction. One end of the water pumping pipe 60 is connected to the water collection tank, and the other end is connected to the water pump.

[0059] A drainage pipe is provided inside the sand cushion layer 10, and the drainage pipe is arranged in a horizontal direction to form a transverse drainage channel; the drainage pipe is pre-buried when the machine-made sand is laid on the surface of the soft foundation structure, and is arranged in a horizontal direction to form a transverse drainage channel;

[0060] The soft soil consolidation preloading soft foundation treatment structure also includes a geomembrane layer 70, which is arranged on the side of the sand cushion layer 10 away from the soft foundation structure. The geomembrane layer 70 is a geomembrane laid on the side of the sand cushion layer 10 away from the soft foundation structure. If the sand cushion layer 10 is directly exposed to the outside, when it rains, rainwater can easily penetrate through the sand cushion layer 10 and enter the soft foundation structure. The increase in the water content of the soft foundation structure may change its original physical and mechanical properties, such as further reducing the strength of the soft soil and increasing its compressibility, which is not conducive to the subsequent consolidation treatment of the soft foundation and engineering construction; and the geomembrane can block the erosion of the sand cushion layer 10 by wind and water flow, prevent the loss of sand materials, ensure the thickness and uniformity of the sand cushion layer 10, and ensure that its drainage and load transfer functions in the soft foundation treatment structure are not affected;

[0061] The soft soil consolidation preloading soft foundation treatment structure also includes a loading layer 80, which is arranged on the side of the geomembrane layer 70 away from the sand cushion layer 10. According to the requirements of the specification and the growth of the soft foundation strength, the loading is constructed step by step on the geomembrane layer 70 to form the loading layer 80;

[0062] By providing at least two layers of sand filling layers 20, at least two lateral drainage surfaces are formed in the soft foundation structure. Compared with single-surface drainage, this multi-surface drainage can significantly improve drainage efficiency, accelerate the consolidation speed of soft soil, shorten the time required to reach the expected consolidation degree, greatly shorten the construction period of soft foundation treatment, create a good working surface for subsequent construction and win precious time; and to a certain extent, it solves the problem that the waterproof sealing membrane in the traditional structure has a limited effect on the isolation of groundwater in the surrounding soil layer. Through the reasonable drainage system constructed by itself, the water in the soft foundation structure is discharged in an orderly manner along the designed lateral drainage surface and other paths, so that the hydraulic state inside the soft foundation structure is relatively stable, and the resistance to external groundwater is enhanced, which can greatly reduce the occurrence of groundwater in the surrounding soil layer infiltrating into the soft foundation area to destroy the drainage consolidation state.

[0063] Further, in this embodiment, the two sand pile filling layers 20 include a first sand pile filling layer and a second sand pile filling layer;

[0064] The two soft soil layers 30 include a first soft soil layer and a second soft soil layer.

[0065] A construction method for a soft soil consolidation preloading soft foundation treatment structure is applied to the soft soil consolidation preloading soft foundation treatment structure as described above, and comprises the following steps:

[0066] S1. Fill the soft foundation with sand to form a soft foundation structure;

[0067] S2, construction of bagged sand well;

[0068] S3. Dig trenches at the boundaries of soft foundation structures;

[0069] S4. Lay machine-made sand and pre-bury drainage pipes;

[0070] S5. Laying geomembrane;

[0071] S6. Carry out construction loading based on the strength of the soft foundation.

[0072] Furthermore, in this embodiment, step S1 specifically includes:

[0073] In the soft soil foundation area below the ground surface, the construction depth is set, and the sand well 40 is measured and laid out. After drilling with a rotary jet drilling rig, machine-made sand is sprayed between the soft soil bottom layer and the first soft soil layer in the soft soil foundation area to form a first sand pile filling layer. After the construction of the first sand pile filling layer is completed, a sand pile is filled between the first soft soil layer and the second soft soil layer to form a second sand pile filling layer. After the two layers of filled sand piles are completed in sequence, a soft foundation structure with two drainage surfaces is formed;

[0074] Compared with single-sided drainage, the consolidation time of this double-sided drainage can theoretically be shortened by 75% under the condition of achieving the same consolidation degree, which greatly shortens the construction period of soft foundation treatment, creates a good working surface for subsequent construction and wins precious time.

[0075] Furthermore, in this embodiment, step S2 specifically includes:

[0076] After the filling sand pile construction is completed, the sand is put into sand bags to form the bagged sand wells, and the bagged sand wells are implanted into the soft foundation structure at intervals along the vertical direction by a drilling rig to form sand wells 40, which form vertical drainage channels inside the soft foundation structure.

[0077] Furthermore, in this embodiment, step S3 specifically includes:

[0078] A boundary water collection tank 50 is formed by excavating a trench mechanically according to a set width and depth around the soft foundation structure, and a plurality of pumping pipes 60 are arranged in the boundary water collection tank 50 at a certain interval, and the pumping pipes 60 extend in the vertical direction; the plurality of pumping pipes 60 are arranged in the boundary water collection tank 50 at equal intervals; the interval between adjacent pumping pipes 60 is 3m to 6m, and the specific interval is selected according to the actual situation;

[0079] After the pumping pipe 60 is set, the boundary water collection tank 50 is filled with machine-made sand to provide a vertical drainage surface for the untreated soft foundation part, which can isolate the untreated soft foundation part from the surrounding groundwater and avoid affecting the subsequent construction of the untreated soft foundation part;

[0080] The pumping pipe 60 is connected to a pumping pump, and water is pumped by the pumping pump to form well point dewatering; this can accelerate the discharge of groundwater in the untreated soft foundation part.

[0081] Furthermore, in this embodiment, step S4 specifically includes:

[0082] On one side of the soft foundation structure away from the second soft foundation soil layer, machine-made sand is laid, and a certain thickness is laid in a direction away from the second soft foundation soil layer to form a sand cushion layer 10; the thickness of the machine-made sand can be selected to be 0.5m to 0.8m, and the specific thickness is selected according to actual conditions;

[0083] A plurality of drainage pipes are buried in the sand cushion layer 10 along the horizontal direction, and the drainage pipes extend transversely to form a transverse drainage channel;

[0084] The sand cushion layer 10 has good water permeability and can further provide a horizontal drainage channel for the pore water in the soft foundation structure. Under the action of pressure difference, the pore water in the soft soil can first be collected into the sand cushion layer 10 through the vertical drainage structure (such as the sand well 40), and then discharged from the soft foundation range along the sand cushion layer 10.

[0085] The lateral drainage channel of the sand cushion layer 10 cooperates with the vertical drainage body to further improve the drainage system, significantly accelerate the drainage and consolidation speed of the soft soil, reduce the porosity of the soft soil, increase the soil strength, effectively improve the engineering properties of the soft soil foundation, and lay a good foundation for subsequent engineering construction.

[0086] Furthermore, in this embodiment, after the construction of the sand cushion layer 10 is completed, a geomembrane is laid on the side of the sand cushion layer 10 away from the soft foundation structure to form a geomembrane layer 70; when laying the geomembrane, it is laid from one end of the sand cushion layer 10 to the other end in sequence to ensure that the geomembrane is flat and straight to avoid wrinkles, distortions, etc., and during the laying process, the geomembrane should be properly tensioned so that it can fit tightly on the surface of the sand cushion layer, but excessive tension should also be avoided to prevent the geomembrane from being torn;

[0087] After the geomembrane is laid, you can choose to conduct a quality inspection on the entire laying area to check whether the geomembrane is damaged, whether the connection parts are firm, whether the seal is good, etc. You can choose to use manual inspection combined with a simple water injection test method for testing; if there are any problems, repair or rectify them in time to ensure that the waterproof and protective effects of the geomembrane meet the expectations.

[0088] Furthermore, in this embodiment, step S6 specifically includes:

[0089] In consideration of the growth of the soft foundation strength, the geomembrane layer 70 is loaded step by step. While the loading is being constructed, all the pumping pipes 60 are connected to the pumps to discharge the accumulated water in the boundary water collection tank 50, so that well point precipitation is generated at the bottom of the boundary water collection tank 50 to form a loading layer 80. All the pumping pipes 60 are connected to the pumps to fully discharge the accumulated water in the boundary water collection tank 50 and accelerate the discharge of groundwater in the soft foundation.

[0090] The above-mentioned construction method can form a horizontal drainage surface at different heights of the soft foundation by filling sand piles inside the soft foundation, changing the traditional single drainage path mode, increasing the dimension of drainage and improving efficiency; the construction of bagged sand wells creates a vertical drainage channel, which cooperates with the horizontal drainage surface to form a three-dimensional drainage system, and the laying of machine-made sand and pre-buried drainage pipes further expand and optimize the entire drainage network, so that the pore water in the soft soil foundation can be quickly discharged through a variety of channels, effectively solving the problems of slow drainage and long consolidation time of the soft soil foundation, accelerating the consolidation speed of soft soil, and shortening the soft foundation treatment period; and this multi-mode combined drainage system does not rely on a single drainage driving mechanism. Compared with relying on only one drainage structure or external unstable factors to promote drainage, it can make the drainage process more stable and reliable based on the characteristics of the soft soil itself and the mutual cooperation between the drainage structures, and it is not easy to cause drainage interruption or sluggishness due to external equipment failure or environmental changes, thereby ensuring the continuity and uniformity of soft soil drainage consolidation.

[0091] In the description of the present disclosure, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present disclosure and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present disclosure.

[0092] For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all of these changes and deformations should fall within the protection scope of the claims of the present disclosure.

Claims

1. A soft soil consolidation preloading soft foundation treatment structure, which is used to be arranged in a soft soil foundation area below the ground surface, wherein the bottom of the soft soil foundation area is a soft soil bottom layer, and is characterized in that: It comprises a sand cushion layer (10), at least two layers of sand filling layers (20) and at least two layers of soft soil layers (30), and the number of layers of the sand filling layers (20) and the soft soil layers (30) is the same; The sand filling layer (20) and the soft foundation soil layer (30) are alternately arranged on the soft foundation soil bottom layer in a vertical direction, the sand filling layer (20) forms a transverse first drainage surface between the soft foundation soil bottom layer and the soft foundation soil layer (30), and the sand filling layer (20) forms a transverse second drainage surface between two adjacent layers of the soft foundation soil layer (30), thereby forming a soft foundation structure having at least two drainage surfaces; The sand cushion layer (10) is arranged on the soft foundation structure; The sand pile filling layer (20) comprises a plurality of sand piles arranged in a horizontal direction, and the cross section of the sand pile in a vertical direction is elliptical; The soft foundation structure is interspersed with a plurality of sand wells (40), and the sand wells (40) form a vertical drainage channel; The soft foundation structure has a groove-shaped boundary water collection groove (50) on the four edges thereof, and the boundary water collection groove (50) is provided with a plurality of water pumping pipes (60) along the vertical direction, and one end of the water pumping pipe (60) is connected to the water collection groove, and the other end is connected to the water pump; A drainage pipe is provided inside the sand cushion layer (10), and the drainage pipe is arranged in a horizontal direction to form a transverse drainage channel; It also comprises a geomembrane layer (70) and a loading layer (80), wherein the geomembrane layer (70) is arranged on a side of the sand cushion layer (10) away from the soft foundation structure, and the loading layer (80) is arranged on a side of the geomembrane layer (70) away from the sand cushion layer (10).

2. The soft soil consolidation preloading soft foundation treatment structure according to claim 2 is characterized in that: The two sand pile filling layers (20) include a first sand pile filling layer and a second sand pile filling layer; The two soft soil layers (30) include a first soft soil layer and a second soft soil layer.

3. A construction method for a soft soil consolidation preloading soft foundation treatment structure, applied to the soft soil consolidation preloading soft foundation treatment structure as claimed in claim 1-2, characterized in that: The following steps are involved: S1. Fill the soft foundation with sand to form a soft foundation structure; S2, construction of bagged sand well; S3, digging trenches on the boundaries of the soft foundation structure; S4. Lay machine-made sand and pre-bury drainage pipes; S5. Laying geomembrane; S6. Carry out construction loading based on the strength of the soft foundation.

4. The method for constructing a soft soil consolidation preloading soft foundation treatment structure according to claim 3 is characterized in that: The step S1 specifically includes: In a soft soil foundation area below the ground surface, a construction depth is set, and a sand well (40) is measured and laid out. After drilling with a rotary jet drilling rig, machine-made sand is sprayed between the soft soil bottom layer and the first soft soil layer in the soft soil foundation area to form a first sand pile filling layer. After the construction of the first sand pile filling layer is completed, a sand pile is filled between the first soft soil layer and the second soft soil layer to form a second sand pile filling layer. After the two layers of filled sand piles are completed in sequence, the soft foundation structure with two drainage surfaces is formed.

5. The method for constructing a soft soil consolidation preloading soft foundation treatment structure according to claim 4 is characterized in that: The step S2 specifically includes: After the construction of the filling sand pile is completed, the sand material is put into sand bags to form the bagged sand wells, and the bagged sand wells are implanted into the soft foundation structure at intervals along the vertical direction using a drilling machine to form sand wells (40). The sand wells (40) form vertical drainage channels inside the soft foundation structure.

6. The method for constructing a soft soil consolidation preloading soft foundation treatment structure according to claim 5, characterized in that: The step S3 specifically includes: A boundary water collection trough (50) is formed by excavating the edges of the soft foundation structure according to a set width and depth using a trenching machine, and a plurality of water pumping pipes (60) are arranged in the boundary water collection trough (50) at a certain interval, and the water pumping pipes (60) extend in a vertical direction; After the pumping pipe (60) is set, the boundary water collection tank (50) is filled with machine-made sand to provide a vertical drainage surface for the untreated soft foundation part; The water pumping pipe (60) is connected to a water pump, and water is pumped by the water pump to form well point dewatering.

7. The method for constructing a soft soil consolidation preloading soft foundation treatment structure according to claim 6, characterized in that: The step S4 specifically includes: Machine-made sand is laid on a side of the soft foundation structure away from the second soft foundation soil layer, and is laid to a certain thickness in a direction away from the second soft foundation soil layer to form a sand cushion layer (10); A plurality of drainage pipes are buried in the sand cushion layer (10) along the horizontal direction, and the drainage pipes extend transversely to form a transverse drainage channel.

8. The method for constructing a soft soil consolidation preloading soft foundation treatment structure according to claim 7, characterized in that: The step S5 specifically includes: After the construction of the sand cushion layer (10) is completed, a geomembrane is laid on a side of the sand cushion layer (10) away from the soft foundation structure to form a geomembrane layer (70).

9. The method for constructing a soft soil consolidation preloading soft foundation treatment structure according to claim 8, characterized in that: The step S6 specifically includes: In combination with the growth of the soft foundation strength, the geomembrane layer (70) is loaded step by step, and while the loading is being constructed, all the pumping pipes (60) are connected to the pump to discharge the accumulated water in the boundary water collection tank (50), so that well point dewatering is generated at the bottom of the boundary water collection tank (50) to form a loading layer (80).

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