Mud foundation grouting lifting construction method combined with drainage consolidation
By pre-laying vertical drainage channels and horizontal drainage networks in the silt foundation, combined with sequential intermittent grouting and real-time monitoring, the problem of secondary settlement caused by the dissipation of excess pore water pressure after grouting and lifting of the silt foundation was solved, achieving efficient drainage consolidation and precise lifting control.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG UNIV OF SCI & TECH
- Filing Date
- 2026-05-27
- Publication Date
- 2026-07-14
Smart Images
Figure CN122383030A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of foundation treatment technology, and particularly relates to a construction method for grouting and lifting of silty foundations with combined drainage consolidation. Background Technology
[0002] Silt geology is characterized by high water content, high compressibility, poor permeability, and long consolidation time. During grouting and lifting operations on silt foundations, high-pressure grouting generates significant excess pore water pressure within the soil, instantly lifting the ground or building. However, after grouting ceases, this excess pore water pressure slowly dissipates over time, causing the soil to undergo drainage consolidation and volume shrinkage, leading to secondary ground settlement. This severely impacts the lifting effect and project safety.
[0003] In the prior art, Chinese invention patent application CN121760404A discloses a method for lifting existing buildings based on additional settlement generated during grouting. To address the problem of "additional settlement" occurring on the side with large settlement during grouting lifting, this method proposes a "spatial isolation + differentiated control" scheme: by arranging a supporting curtain around the main lifting area to enclose the large settlement area and prevent grout leakage; a transition zone is set up to form a grouting isolation layer to block the lateral transmission of stress; and a stabilization zone is set up primarily for reinforcement, with minimal or no lifting. However, in this method, the curtain wall acts as a lateral barrier, and its drainage channels are mainly the pre-reserved drainage outlets on the curtain wall. The drainage path is long and the drainage area is limited, making it difficult to quickly dissipate the high pore water pressure caused by large-area grouting in deep silt layers. Furthermore, this method relies on the construction of the curtain wall, limiting its applicability to scenarios involving large-area site lifting or lifting existing buildings where curtain walls cannot be installed.
[0004] Chinese invention patent application CN121781576A discloses a self-draining consolidation and pre-reinforcement pile foundation for soft soil foundations. It employs a hollow reinforced concrete pile foundation with radially extendable lateral ribs as drainage channels, achieving drainage consolidation and pre-reinforcement through the pile itself. Chinese invention patent application CN121781574A discloses a segmented drainage combined pile and consolidation calculation method. It uses a segmented pile structure with "upper drainage, lower non-drainage," where the upper part uses a permeable shell to form radial and vertical drainage channels, and the lower part is an impermeable rigid pile providing end bearing capacity. Both of these solutions are precast pile products integrating drainage and load-bearing. Their construction methods, structural forms, and application scenarios differ from the grouting method used to raise the foundation of existing buildings and structures, and are not suitable for grouting and raising projects of existing building foundations.
[0005] Therefore, there is an urgent need for a method that can efficiently drain excess pore water during the grouting and lifting process, has a wider range of applications, and can work in conjunction with grouting construction to effectively solve the problem of secondary settlement after grouting and lifting of silty foundations. Summary of the Invention
[0006] The purpose of this invention is to provide a construction method for grouting and lifting silty foundations with combined drainage consolidation, which effectively solves the problem of secondary settlement caused by the dissipation of excess pore water pressure after grouting and lifting of silty foundations in the prior art.
[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a construction method for grouting and lifting of silty foundation with combined drainage consolidation, including the following steps: S1, construction preparation and site survey, determining the grouting and lifting range and depth parameters.
[0008] S2. Within the area to be lifted, several vertical drainage bodies are set at preset intervals. The vertical drainage bodies penetrate the silt layer or enter the relatively permeable soil layer below the silt layer, and the top of the vertical drainage bodies protrudes above the ground.
[0009] S3. Lay a sand cushion layer or lay a horizontal drainage network at the top of the vertical drainage body to connect the upper ends of each vertical drainage body to form a three-dimensional drainage network, and set up a collection well or drainage outlet.
[0010] S4. In the area to be raised, several grouting holes are arranged at a preset interval, and the vertical drainage body is located at the center of the grouting hole grid; the depth of the grouting holes reaches the designed lifting level; grouting pipes are lowered into the grouting holes, and grout outlet sections are set at the bottom of the grouting pipes.
[0011] S5. Perform intermittent pressure grouting to the bottom of the grouting hole through the grouting pipe. During the grouting process, collect the uplift data in real time through settlement monitoring points that are pre-installed on the building foundation or ground and observe the water discharge of the vertical drainage body.
[0012] S6. Once the lifting volume reaches the design requirements, reduce the grouting pressure to enter the pressure stabilization stage. Maintain the pressure stabilization for a period of time to allow the grout to fully solidify and complete the discharge of residual excess pore water. After the pressure stabilization is completed, seal the grouting holes, dismantle the drainage system or block the drainage system to complete the construction.
[0013] Furthermore, in step S5, when the lifting amount reaches the preset lifting amount threshold of this sequence, or the lifting rate decreases significantly to zero, or the water discharge from the vertical drainage body increases significantly, the grouting of this sequence is stopped and the pressure stabilization interval is entered. The excess pore water generated by grouting is discharged to the ground through the pre-laid vertical drainage body and horizontal drainage pipe network, and the soil undergoes drainage consolidation.
[0014] When the monitoring data shows that the settlement rate tends to stabilize and the outflow of water from the vertical drainage body decreases significantly, it indicates that the excess pore water caused by this grouting sequence has been fully discharged.
[0015] If the cumulative lifting amount has not yet reached the designed lifting amount, the next grouting sequence is carried out to accumulate grouting pressure again to achieve further lifting. This cycle continues until the lifting amount reaches the design requirements.
[0016] Furthermore, in step S2, the vertical drainage body is a plastic drainage board or a bagged sand well.
[0017] Furthermore, in step S1, a geological survey is conducted on the thickness, water content, permeability coefficient, and distribution of the underlying soil layer in the area to be lifted.
[0018] Furthermore, in step S4, the spacing between the grouting holes is 1.5m-3.0m; the vertical drainage body is located at the center of the grouting hole grid, so that the distance from each vertical drainage body to each grouting hole around it is equal.
[0019] Furthermore, in step S5, the grouting pressure is controlled between 0.5MPa and 2.0MPa, and the grouting volume per sequence does not exceed the preset value.
[0020] Furthermore, in step S5, the grout is cement grout, cement-water glass two-component grout, or cement grout mixed with micro-expansion agent, and the initial setting time of the grout is controlled between 30 min and 120 min.
[0021] Furthermore, the vertical drainage body and the grouting pipe are pre-tied and combined to form an integrated "drainage-grouting" unit, which is then simultaneously driven into the foundation.
[0022] Furthermore, settlement monitoring points are set up during construction to monitor the uplift and settlement changes in real time and dynamically adjust the grouting parameters.
[0023] Furthermore, in step S5, the monitoring frequency of the settlement monitoring points shall be no less than 30 seconds per time during the grouting stage and no less than 5 minutes per time during the pressure stabilization interval.
[0024] Compared with the prior art, the beneficial technical effects of the present invention are: (1) Synchronous drainage consolidation to reduce secondary settlement: By pre-laying vertical drainage channels before grouting and lifting, the excess pore water generated by grouting can be discharged quickly and nearby, greatly shortening the soil consolidation time and effectively reducing post-construction secondary settlement.
[0025] (2) High drainage efficiency: Vertical drainage boards or sand wells are used to form a three-dimensional drainage network. The drainage path is short and the drainage area is large. Compared with the existing technology that only relies on the side drainage outlet of the curtain wall, the drainage efficiency is significantly improved.
[0026] (3) Wide range of applicable scenarios: It does not rely on the setting of curtain walls and can be applied to various engineering scenarios such as large-area site lifting and existing building lifting and correction without the conditions to set curtain walls.
[0027] (4) Simple construction and controllable cost: The plastic drainage board insertion technology is mature and inexpensive, and it is smoothly connected with the grouting construction, so the overall construction cost increases only slightly.
[0028] (5) Controllable lifting effect: By monitoring settlement data in real time and combining it with the sequential intermittent grouting process, the lifting process can be precisely controlled to avoid excessive or insufficient lifting. Attached Figure Description
[0029] Figure 1 This is a process flow diagram of the grouting and lifting construction method for silt foundations combined with drainage consolidation according to the present invention.
[0030] Figure 2 This is a schematic diagram of the planar arrangement of the vertical drainage body and grouting holes in the area to be lifted according to the present invention.
[0031] Figure 3 This is a cross-sectional view of the arrangement structure of the vertical drainage channel, horizontal drainage system and grouting holes of the present invention. Detailed Implementation
[0032] This invention provides a combined drainage consolidation grouting and lifting construction method for silt foundations. It is a combined drainage consolidation construction method that performs grouting and lifting in soft soil foundations such as silt and prevents secondary settlement after construction. It is applicable to foundation lifting and correction, foundation reinforcement and settlement control projects of existing buildings and structures.
[0033] like Figure 1 As shown, the present invention specifically includes the following steps: S1, construction preparation and site survey.
[0034] Geological investigations were conducted to determine the thickness, water content, permeability coefficient, and distribution of underlying soil layers in the area to be lifted, in order to determine the grouting lift range and depth parameters.
[0035] S2. Lay out vertical drainage channels.
[0036] Within the area to be raised, several vertical drainage bodies are installed at preset intervals to form a vertical drainage network.
[0037] Vertical drainage bodies penetrate the silt layer or enter the relatively permeable soil layer below the silt layer; the top of the vertical drainage body protrudes above the ground to a certain height or is connected to the horizontal drainage system.
[0038] The vertical drainage body is a plastic drainage board or a bagged sand well.
[0039] S3. Install a horizontal drainage system.
[0040] like Figure 3As shown, a sand cushion layer or a horizontal drainage network is laid at the top of the vertical drainage body to connect the upper ends of each vertical drainage body, forming a three-dimensional drainage network, and a collection well or drainage outlet is set up.
[0041] S4. Lay out grouting holes.
[0042] Within the area to be raised, several grouting holes are arranged at preset intervals, with a spacing of 1.5m-3.0m. The depth of the grouting holes reaches the designed lifting level; grouting pipes are lowered into the grouting holes, and grout outlet sections are set at the bottom of the grouting pipes.
[0043] like Figure 2 As shown, the vertical drainage bodies are located at the center of the grouting hole grid, ensuring that each vertical drainage body is equidistant from all surrounding grouting holes. The lower limit of this distance prevents high-pressure grouting from directly penetrating or damaging adjacent vertical drainage bodies, avoiding grout blockage and failure of drainage channels, and preventing the excess pore water pressure generated by grouting from being instantly discharged through the nearest drainage body before sufficient lifting force has accumulated. The upper limit of this distance ensures that the seepage path of excess pore water generated at the grouting point in the silt is short enough to allow it to be effectively collected and discharged by the drainage network during grouting intervals.
[0044] Vertical drainage bodies and grouting pipes can be pre-tied and combined to form an integrated "drainage-grouting" unit, which is then simultaneously driven into the foundation.
[0045] S5, pressure grouting lifting and synchronous drainage.
[0046] Intermittent pressure grouting is performed in sequence to the bottom of the grouting hole through the grouting pipe. During the grouting process, the uplift data is collected in real time by the settlement monitoring points pre-installed on the building foundation or ground and the water discharge of the vertical drainage body is observed: first, grouting is performed, and the grout spreads, splits and compacts the soil in the silt layer to form a grout vein support body, which lifts the upper soil and building.
[0047] When the uplift reaches the preset uplift threshold for this sequence (the preset uplift threshold is the total designed uplift divided by the expected grouting sequence number), or the uplift rate decreases significantly and approaches zero, or the outflow from the vertical drainage body increases significantly, the grouting for this sequence is stopped and a pressure stabilization interval begins. The excess pore water generated by grouting is discharged to the ground through the pre-installed vertical drainage body and horizontal drainage system, and the soil undergoes drainage consolidation. When the monitoring data shows that the settlement rate tends to stabilize and the outflow from the drainage board decreases significantly, it indicates that the excess pore water caused by the grouting for this sequence has been fully discharged. At this time, if the cumulative uplift has not yet reached the designed uplift, the next grouting sequence is carried out to re-accumulate grouting pressure to achieve further uplift. This cycle continues until the uplift reaches the design requirements.
[0048] The grouting pressure is controlled between 0.5MPa and 2.0MPa, and the grouting volume in a single sequence does not exceed the preset value, in order to avoid excessive disturbance to the soil.
[0049] The grouting slurry is cement slurry, cement-water glass two-component slurry, or cement slurry mixed with micro-expansion agent. The initial setting time of the slurry is controlled between 30 min and 120 min.
[0050] Settlement monitoring points are set up during construction to monitor the uplift and settlement changes in real time and dynamically adjust grouting parameters. Settlement monitoring points are set up on the building foundation or ground, and the monitoring frequency is no less than once every 30 seconds during the grouting stage and no less than once every 5 minutes during the pressure stabilization interval.
[0051] S6. Voltage Stabilization and Maintenance.
[0052] Once the lifting volume reaches the design requirements, reduce the grouting pressure to enter the pressure stabilization stage. Maintain the pressure stabilization for a period of time to allow the grout to fully solidify and complete the discharge of residual excess pore water. After the pressure stabilization is completed, seal the grouting holes, dismantle the drainage system or block the drainage system to complete the construction.
[0053] The present invention will be further described in detail below through specific embodiments and comparative examples.
[0054] Example 1: An existing building is located on a silty soft soil foundation. The silt layer is approximately 8m thick, with a water content of approximately 65% and a permeability coefficient of approximately 2×10⁻⁶. -7 The ground speed is cm / s, and the lower part is a layer of silty clay. The building tilted due to uneven settlement of the foundation.
[0055] In this embodiment, the tilted building is lifted and corrected using the combined drainage consolidation grouting and lifting construction method for silt foundations provided by the present invention.
[0056] The construction process is as follows: (1) Construction preparation and geological investigation: It was further determined that the thickness of the silt layer was 8.2m, the water content was about 65%, and the lower part was a silty clay layer with a permeability coefficient of about 2×10. -7 cm / s.
[0057] (2) Install vertical drainage channels: In the pre-set raised area around the foundation of the building, install plastic drainage boards in a quincunx pattern with a spacing of 1.5m×1.5m; the drainage boards are inserted to a depth of 9.0m, penetrating the silt layer and entering the lower silty clay layer by about 0.8m; the top of the drainage boards protrudes about 0.3m above the ground, and a sand cushion layer is laid to connect the tops of each drainage board, and a water collection well is set up.
[0058] (3) Arrangement of grouting holes: Grouting holes are arranged in a quincunx pattern with a spacing of 2.0m; for example Figure 2 and Figure 3As shown, the vertical drainage body is located at the center of the plum blossom-shaped grid of grouting holes, that is, the distance from each vertical drainage body to the three grouting holes around it is about 1.15m; the hole depth is 7.5m, and the grouting pipe is lowered in, with a grout outlet section set at the bottom of the grouting pipe.
[0059] (4) Sequential intermittent grouting and synchronous drainage: Settlement monitoring points are set up on the building foundation and ground. The monitoring frequency during the grouting stage is 30s / time, and the pressure stabilization interval is 5min / time.
[0060] Cement-water glass dual-liquid grout was used, with the grouting pressure controlled at 1.2 MPa and the single-sequence grouting volume not exceeding 0.8 m. 3 To control soil disturbance.
[0061] First-stage grouting: After grouting begins, the grout spreads and splits within the silt layer, causing a continuous increase in lift. When the lift reaches approximately 40 mm (about 1 / 3 of the total lift of 120 mm), and a significant increase in water discharge from the drainage board is observed, it is determined that the excess pore water pressure has reached a high level. Grouting is then stopped, and a pressure-stabilizing intermittent period begins. During this intermittent period, continuous water discharge from the plastic drainage board is observed, with a larger discharge volume in the first 10 minutes, which gradually decreases. After 30 minutes, the discharge volume decreases significantly, and settlement monitoring data shows that the settlement rate tends to stabilize, indicating that the excess pore water caused by this grouting stage has been fully discharged.
[0062] Second grouting: Grouting is performed again to re-accumulate grouting pressure, and the lift continues to increase; when the cumulative lift reaches approximately 80mm, a signal of increased water flow appears again, and grouting is stopped to enter the intermittent drainage stage. Observe for 30 minutes again; after the water flow significantly decreases and the settlement tends to stabilize, the next grouting sequence is performed.
[0063] Third-stage grouting: Grouting is performed again. When the soil has risen to a cumulative height of about 125 mm, the rising rate decreases significantly. It is determined that the soil has reached the rising limit of the current stage, and grouting is stopped.
[0064] (5) Pressure stabilization and curing: Reduce the grouting pressure to 0.3MPa for pressure stabilization, maintain the pressure stabilization for about 60 minutes to complete the residual drainage and grout solidification; then seal the grouting hole and block the drainage system.
[0065] This embodiment achieved a cumulative uplift of approximately 125 mm, slightly exceeding the design value. Continuous monitoring after construction revealed a slight settlement of approximately 3 mm on days 1-3, due to instantaneous compression of the shallow soil; settlement on days 3-60 was only approximately 5 mm; the cumulative settlement over 60 days was approximately 8 mm, with a settlement rate of only about 6.4%, far lower than the 35% settlement rate in Comparative Example 1. The building tilt was effectively corrected, and no significant changes were observed during subsequent 90 days of monitoring.
[0066] Comparative Example 1: This comparative example is under the same geological conditions as Example 1, and the same building is lifted and corrected.
[0067] This comparative example uses a scheme similar to the curtain wall + reserved drainage outlet disclosed in Chinese invention patent CN121760404A to lift and correct the building.
[0068] The construction process is as follows: (1) Drill holes around the base of the building to form a curtain wall with a depth of 9m and reserve lateral drainage outlets on the curtain wall; the drainage outlets are spaced about 6m apart and the cross-sectional dimensions of the drainage outlets are 100mm×100mm.
[0069] (2) Grouting holes are laid out in the inner area of the curtain wall, with a hole spacing of about 2.0m and a hole depth of 7.5m, and grouting pipes are lowered in.
[0070] (3) Grouting and lifting were carried out using cement-water glass double-liquid grout at a pressure of 1.2 MPa, in three stages; pressure was stabilized for 30 minutes after each stage. During the grouting process, a small amount of muddy water was observed to be discharged from the curtain wall drainage outlet.
[0071] In this comparative example, grouting was stopped after the total grouting lift reached approximately 120mm. Continuous monitoring was conducted after construction. After 60 days, the cumulative settlement was approximately 42mm, representing a settlement rate of 35%, and the building began to tilt again.
[0072] The reason for the above results in this comparative example is that the curtain wall mainly serves to block grout and stress leakage, and its drainage outlets are only lateral and local drainage channels with long drainage paths and limited areas. The large amount of excess pore water generated by grouting cannot be fully discharged in a short time, and most of the water pressure dissipates slowly within several days after the completion of grouting, resulting in continuous consolidation and settlement of the soil and a high settling rate.
[0073] Example 2: A large-area stockpile is located on a newly filled silt foundation. The silt layer is about 12m thick with a water content of about 72%. The lower part is a silty clay layer with a permeability coefficient of about 1×10⁻⁶. -7 cm / s, the overall height needs to be raised by about 200mm.
[0074] In this embodiment, the sludge foundation grouting and lifting construction method with combined drainage consolidation provided by the present invention is used to lift the entire stockpile.
[0075] The construction process is as follows: (1) Construction preparation and geological investigation: It was further determined that the thickness of the silt layer was about 12m, the water content was about 72%, and the permeability coefficient was about 1×10 -7 cm / s.
[0076] (2) The construction of the integrated unit of "drainage-grouting" is adopted: the plastic drainage board and the grouting pipe are pre-tied together; the grouting holes are arranged in a quincunx pattern around the foundation of the stockpile and in the pre-set lifting area inside, with a hole spacing of 2.0m; the plastic drainage board is located in the center of the grouting hole grid, about 1.15m away from each grouting hole; the integrated unit is driven into the foundation at the same time using a jackhammer; the plastic drainage board penetrates the silt layer and enters the lower silty clay layer about 1.0m.
[0077] (3) A horizontal drainage network is laid at the top of the integrated unit to connect each plastic drainage board and connect to the collection well, such as Figure 3 As shown.
[0078] (4) The grouting uses cement grout mixed with micro-expansion agent, and the grouting pressure is controlled at 1.5MPa. The total designed lifting amount is 200mm, and the grouting is divided into five stages, with a preset lifting amount of about 40mm for each stage.
[0079] Settlement monitoring points are set up before grouting, and the monitoring frequency during the grouting stage is once per minute. The construction process follows a cyclical pattern of "grouting and lifting → monitoring and judgment (lifting amount reaches the standard / water flow surges) → stopping grouting → intermittent drainage and consolidation → settlement stabilization → next grouting sequence", with each intermittent drainage session lasting approximately 40-60 minutes.
[0080] (5) After the lifting amount reaches about 205mm, the pressure stabilization stage begins. After stabilizing for about 90 minutes, the hole is sealed.
[0081] In this embodiment, monitoring was conducted continuously for 90 days after construction, with a cumulative settlement of approximately 15mm and a settlement rate of approximately 7.3%. The overall flatness of the site was good, meeting the requirements for subsequent use.
[0082] This invention effectively solves the problem of secondary settlement caused by the dissipation of excess pore water pressure after grouting and lifting of silty foundations in the prior art, and realizes the synchronous and coordinated operation of grouting and lifting and drainage consolidation, thereby improving the stability and controllability of the lifting effect.
[0083] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.
Claims
1. A method for grouting and lifting construction of silty foundations with combined drainage consolidation, characterized in that, Includes the following steps: S1. Construction preparation and site survey, determining the grouting lift range and depth parameters; S2. Within the area to be lifted, several vertical drainage bodies are set at preset intervals. The vertical drainage bodies penetrate the silt layer or enter the relatively permeable soil layer below the silt layer, and the top of the vertical drainage bodies protrudes above the ground. S3. Lay a sand cushion layer or lay a horizontal drainage network at the top of the vertical drainage body to connect the upper ends of each vertical drainage body to form a three-dimensional drainage network, and set up a collection well or drainage outlet. S4. In the area to be lifted, several grouting holes are arranged at a preset interval, and the vertical drainage body is located at the center of the grouting hole grid; the depth of the grouting holes reaches the designed lifting level; grouting pipes are lowered into the grouting holes, and grout outlet sections are set at the bottom of the grouting pipes; S5. Perform intermittent pressure grouting to the bottom of the grouting hole through the grouting pipe. During the grouting process, collect the uplift data in real time through settlement monitoring points that are pre-installed on the building foundation or ground and observe the water discharge of the vertical drainage body. S6. Once the lifting amount reaches the design requirements, reduce the grouting pressure to enter the pressure stabilization stage. Maintain the pressure stabilization for a period of time to allow the grout to fully solidify and complete the discharge of residual excess pore water. After the pressure stabilization is completed, the grouting holes are sealed, and the drainage system is dismantled or blocked to complete the construction.
2. The method for grouting and lifting silt foundations with combined drainage consolidation according to claim 1, characterized in that, In step S5, when the lifting amount reaches the preset lifting amount threshold of this sequence, or the lifting rate decreases significantly to zero, or the water discharge from the vertical drainage body increases significantly, the grouting of this sequence is stopped and the pressure stabilization interval is entered. The excess pore water generated by grouting is discharged to the ground through the pre-laid vertical drainage body and horizontal drainage pipe network, and the soil undergoes drainage consolidation. When the monitoring data shows that the settlement rate tends to stabilize and the outflow of water from the vertical drainage body is significantly reduced, it indicates that the excess pore water caused by this grouting sequence has been fully discharged. If the cumulative lifting amount has not yet reached the designed lifting amount, the next grouting sequence is carried out to accumulate grouting pressure again to achieve further lifting. This cycle continues until the lifting amount reaches the design requirements.
3. The method for grouting and lifting silt foundations with combined drainage consolidation according to claim 1, characterized in that, In step S2, the vertical drainage body is a plastic drainage board or a bagged sand well.
4. The method for grouting and lifting silt foundations with combined drainage consolidation according to claim 1, characterized in that, In step S1, a geological survey is conducted to investigate the thickness, water content, permeability coefficient, and distribution of underlying soil layers in the area to be lifted.
5. The method for grouting and lifting silt foundations with combined drainage consolidation according to claim 1, characterized in that, In step S4, the spacing between the grouting holes is 1.5m-3.0m; The vertical drainage body is located at the center of the grouting hole grid, such that each vertical drainage body is equidistant from all the grouting holes around it.
6. The method for grouting and lifting a silty foundation with combined drainage consolidation according to claim 2, characterized in that, In step S5, the grouting pressure is controlled between 0.5MPa and 2.0MPa, and the grouting volume per sequence does not exceed the preset value.
7. The method for grouting and lifting a silty foundation with combined drainage consolidation according to claim 6, characterized in that, In step S5, the grout is cement grout, cement-water glass two-component grout, or cement grout mixed with micro-expansion agent, and the initial setting time of the grout is controlled between 30 min and 120 min.
8. The method for grouting and lifting silt foundations with combined drainage consolidation according to claim 1, characterized in that, The vertical drainage body and the grouting pipe are pre-tied together to form an integrated "drainage-grouting" unit, which is then driven into the foundation simultaneously.
9. The method for grouting and lifting construction of silt foundation with combined drainage consolidation according to claim 1, characterized in that, Settlement monitoring points are set up during construction to monitor the uplift and settlement changes in real time and dynamically adjust grouting parameters.
10. The method for grouting and lifting construction of silt foundation with combined drainage consolidation according to claim 9, characterized in that, In step S5, the monitoring frequency of the settlement monitoring points shall be no less than 30 seconds per time during the grouting stage and no less than 5 minutes per time during the pressure stabilization interval.