A method for preventing ground surface deformation caused by groundwater level rising in a thick fill area

Abstract

This invention discloses a method for preventing surface deformation caused by groundwater level rise in thick fill areas, belonging to the field of roadbed engineering technology. The method includes the following steps: excavating longitudinal underground trenches on both sides of the main roadbed, with the trenches arranged asymmetrically at different depths; excavating a seepage trench below the shallow trench and a collection well on one side of the deep trench; laying an arched waterproof layer at the bottom layer; and sequentially laying a composite capillary barrier layer, a drainage transition layer, a vibration damping transition layer, and the roadbed layer on the upper surface of the waterproof layer; draining the water collected by the drainage transition layer into the underground trenches on both sides, and diverting the water blocked by the waterproof layer into the seepage trench and the deep trench. This invention, by constructing an asymmetrical lateral drainage structure and utilizing the composite capillary barrier layer and the waterproof layer for synergistic isolation, and the vibration damping transition layer to weaken vibration transmission, achieves coordinated prevention and control of groundwater level rise, capillary rise, and vibration damage in thick fill areas, effectively suppressing roadbed moisture accumulation and surface deformation, and improving the long-term service performance of the road.

Description

Technical Field

[0001] This invention belongs to the field of roadbed engineering technology, specifically relating to a method for preventing surface deformation caused by the rise of groundwater level in thick fill areas. Background Technology

[0002] With the rapid construction of large-scale, thick-layer fill and transportation infrastructure in new urban areas, the problem of surface deformation caused by rising groundwater levels is becoming increasingly prominent. In areas with thick fill layers, the distinct stratification of the fill structure and significant differences in permeability easily lead to localized waterlogging, capillary water rise, and internal moisture accumulation in the roadbed. Simultaneously, the long-term repeated loads and vibrations from vehicles on roads further exacerbate upward water migration and damage to shallow structures. Related studies indicate that rising groundwater levels, water migration from the roadbed, and the "bowl effect" can all lead to shallow soil moisture accumulation, structural damage, and surface deformation.

[0003] The difficulty of the aforementioned technical problems lies in the significant coupling between groundwater level rise, capillary upwelling, interlayer perched water, and vehicle vibration. These factors act in a concealed and delayed manner, making it difficult for a single drainage or water-blocking measure to simultaneously address isolation, drainage, vibration reduction, and dynamic control. Inadequate control can easily lead to roadbed softening, pavement cracking, settlement, heave, and increased maintenance costs, severely impacting the long-term safe operation of roads and related infrastructure. Currently, existing solutions to these technical problems mainly fall into the following categories: (1) Drainage and diversion technology: Roadbed water is drained by setting up side ditches, blind ditches, drainage pipes, sump wells and gravel drainage layers, but this scheme lacks systematic suppression of capillary rise and interlayer water retention; (2) Waterproofing and seepage prevention technology: physical barriers are used to reduce the rise of moisture, but this solution has durability risks in large areas of thick fill, and the high cost leads to poor construction economy. (3) Subbase gradation and capillary inhibition technology: Moisture migration is controlled by gradation materials and layered filling, but this scheme only relies on the passive defense of structural materials and lacks the ability to dynamically and actively control the groundwater level. (4) Monitoring and automatic control technology: Drainage regulation is carried out using sensors and external systems, but this scheme is often designed separately from the main civil engineering structure of the roadbed, making it difficult to form a complete internal integrated defense line. Summary of the Invention

[0004] To address the problems existing in the prior art, a method for preventing surface deformation caused by groundwater level rise in thick fill areas is provided. This invention constructs an asymmetric lateral drainage structure, while simultaneously utilizing a composite capillary barrier layer and a water-resistant layer to synergistically block vibrations, and a vibration-damping transition layer to weaken vibration transmission. This achieves coordinated prevention and control of groundwater level rise, capillary uplift, and vibration damage in thick fill areas, effectively suppressing roadbed moisture accumulation and surface deformation, and improving the long-term service performance of roads.

[0005] This invention provides a method for preventing surface deformation caused by groundwater level rise in thick fill areas, comprising the following steps: S1: Excavate longitudinal underground ditches on both sides of the main roadbed. The underground ditches on both sides are arranged asymmetrically in shallow and deep directions. Excavate a seepage ditch below the shallow underground ditch and a water collection well on one side of the deep underground ditch. S2: An arched waterproof layer is laid on the subgrade layer, and a composite capillary barrier layer, a drainage transition layer, a shock-absorbing transition layer, and a road base layer are laid sequentially on the upper surface of the waterproof layer. S3: The water collected in the drainage transition layer is discharged into the underground ditches on both sides. The water blocked by the water-proof layer is directed into the infiltration ditch and the deep side underground ditch. The water collected in the deep side underground ditch is introduced into the water collection well. The water collected in the shallow side underground ditch and the infiltration ditch is discharged naturally along the longitudinal direction of the road. S4: Install a water pump in the collection well. When the water level is higher than the upper limit threshold, the water pump will pump out the water in the collection well.

[0006] Furthermore, in S1, the main body of the roadbed is leveled, rolled and compacted, sharp stones on the surface are removed, and an arched transverse slope foundation with a high middle and low sides is rolled out. At the same time, a culvert is dug on both sides.

[0007] Furthermore, the waterproof layer is made of a highly durable, flexible, and impermeable material.

[0008] Furthermore, the composite capillary layer is made of silty clay or modified clay as the main material, and mixed with silt or fine sand to form a dense composite mixture.

[0009] Furthermore, the guide transition layer uses graded crushed stone or coarse sand with a large pore structure as a highly permeable substrate, and is laid and compacted in layers.

[0010] Furthermore, the damping transition layer is constructed using an elastic damping material.

[0011] Furthermore, the seepage trench is made of a highly permeable material.

[0012] Furthermore, in S2, a pavement layer is laid on the upper surface of the road base layer.

[0013] Furthermore, the deep side culvert is provided with a confluence hole, which is located below the waterproof layer, so that the water blocked by the waterproof layer can be directed into the deep side culvert.

[0014] Furthermore, it also includes: A water level monitoring device, used to monitor the water level in a collection well; The drain pipe has one end connected to the water pump and the other end extending to the outside of the collection well; When the water level is higher than the upper limit threshold, the water pump pumps out the water in the collection well through the drain pipe. When the water level is lower than or equal to the lower limit threshold, the water pump stops.

[0015] The method for preventing surface deformation caused by groundwater level rise in thick fill areas provided by the present invention has the following beneficial effects: 1. This invention proposes an integrated prevention approach of "blocking-lateral drainage-regulation-vibration reduction", which incorporates micro-arch composite seepage prevention, combined drainage, dynamic regulation and source vibration reduction into the same technical system. This overcomes the limitations of existing single-method technologies and achieves coordinated prevention and control of groundwater level rise, capillary rise and vibration damage in thick fill areas. It effectively suppresses roadbed wet accumulation and surface deformation and improves the long-term service performance of roads.

[0016] 2. This invention employs a water-resistant layer and a composite capillary barrier layer to form a micro-arched barrier structure. The composite capillary barrier layer is a reasonably graded and dense mixture of silty clay amendment and silt or fine sand, which, together with the water-resistant layer, forms a composite seepage barrier, effectively cutting off the upward migration channels of underground liquid water and water vapor, and preventing the intrusion and damage to the upper roadbed caused by the rise of the groundwater level.

[0017] 3. This invention utilizes a slightly arched slope to laterally divert groundwater and stagnant water inside the roadbed to both sides, and promptly guides the stagnant water from the upper part into the underground ditch through the drainage transition layer, achieving a combined effect of blocking and lateral flow guidance, avoiding the accumulation of water in the core area of ​​the roadbed, and forming a proactive defense mechanism of "blocking-drainage" synergy.

[0018] 4. This invention constructs an asymmetrical lateral drainage structure on both sides of the road, with shallow side culverts and base seepage trenches stacked vertically, and deep side culverts and collection wells arranged side by side, forming a three-dimensional drainage and diversion system. This system promptly removes groundwater and capillary water intercepted by the impermeable layer and discharges it uniformly through pumps, effectively protecting the stability of the roadbed core area. Simultaneously, it is equipped with a water level monitoring device to automatically implement drainage regulation based on changes in the groundwater level, achieving dynamic and proactive control of the groundwater level. This overcomes the lag of traditional static isolation or conventional drainage and enhances the proactive prevention and control capabilities against the continuous rise of groundwater levels in thick fill areas.

[0019] 5. This invention sets up a vibration-damping transition layer below the roadbed to weaken the transmission of vehicle cyclic loads and vibrations to the lower fill and water migration channels, thereby suppressing the dynamic effect of vibration on capillary water rise from the source. It achieves synergistic control of vibration reduction, isolation, and strong drainage. Through the coordinated layout of materials and structures, it simultaneously meets the engineering requirements of groundwater isolation, active regulation, and vibration reduction to suppress capillary rise in thick fill areas, effectively suppressing roadbed wetting and softening, pavement cracking, and settlement and heave, making it more applicable to engineering projects. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of the overall structure disclosed in the embodiments of the present invention; Figure 2 This is a top view of the overall structure disclosed in the embodiment of the present invention; Figure 3 This is a system control flowchart disclosed in an embodiment of the present invention; Explanation of reference numerals in the attached figures: 1. Pavement layer; 2. Subbase layer; 3. Vibration damping transition layer; 4. Drainage transition layer; 5. Composite capillary barrier layer; 6. Waterproof layer; 7. Underground ditch; 8. Seepage ditch; 9. Pump; 10. Collection well; 11. Drainage pipe; 12. Water level monitoring device. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0022] like Figures 1-3 As shown, this embodiment discloses a method for preventing surface deformation caused by groundwater level rise in thick fill areas, including the following steps: S1: Excavate longitudinal underground ditches 7 on both sides of the main roadbed. The underground ditches 7 on both sides are arranged in an asymmetrical depth. The upper surfaces of the two underground ditches 7 are at the same horizontal level, but the depths of the two underground ditches 7 are different. A seepage ditch 8 is excavated below the shallow underground ditch 7, and a water collection well 10 is excavated on one side of the deep underground ditch 7. The deep underground ditch 7 and the water collection well 10 are set up side by side. S2: An arched waterproof layer 6 is laid on the subgrade layer. On the upper surface of the waterproof layer 6, a composite capillary layer 5, a guide transition layer 4, a shock-absorbing transition layer 3, and a subgrade layer 2 are laid in sequence. The pavement layer 1 is laid on the upper surface of the subgrade layer 2. Both the waterproof layer 6 and the pavement layer 1 are designed to be higher in the middle and lower on both sides, and the arching of each layer is matched so that they are attached in sequence. The upper surfaces of the two underground ditches 7 are flush with the two sides of the pavement layer 1, so as to facilitate better drainage of the pavement layer 1. Among them, the composite subbase barrier and deep well drainage system can be combined with the large-area thick-layer filling project in large urban new areas for overall planning and large-area pre-paving. After the foundation treatment is completed and the groundwater level rise channel is cut off, the road base layer 2 and pavement layer 1 are specifically paved above the planned traffic artery area. S3: The water collected by the drainage transition layer 4 is discharged into the underground ditches 7 on both sides. The water includes stagnant water and condensate inside the roadbed. The water blocked by the water-proof layer 6 flows bidirectionally down the slope and is directed into the infiltration ditch 8 and the deep side underground ditch 7 respectively. The water includes groundwater and capillary water. The deep side underground ditch 7 acts as a water collection hub to introduce the collected water into the water collection well 10. The water collected by the shallow side underground ditch 7 and the infiltration ditch 8 is discharged naturally along the longitudinal direction of the road. S4: Install a water pump 9 in the water collection well 10. When the water level is higher than the upper limit threshold, the water pump 9 will pump out the water in the water collection well 10.

[0023] By adopting an integrated prevention approach of "blocking, lateral drainage, regulation, and vibration reduction," micro-arch composite seepage prevention, combined drainage, dynamic regulation, and source vibration reduction are incorporated into the same technical system. This overcomes the limitations of existing single-method technologies and achieves coordinated prevention and control of groundwater level rise, capillary rise, and vibration damage in thick fill areas. It effectively suppresses roadbed wetness and surface deformation, and improves the long-term service performance of roads.

[0024] In S1, the main body of the roadbed is leveled, rolled and compacted, and sharp stones on the surface are removed. A slightly arched cross slope foundation with a high middle and low sides is rolled out to lay an arched waterproof layer 6. At the same time, a culvert 7 is dug on both sides. A base seepage ditch 8 is dug directly below the shallow culvert 7, and a water collection well 10 is dug next to the deep culvert 7.

[0025] The waterproof layer 6 is made of a highly durable and flexible impermeable material and is laid continuously along the slightly arched transverse slope foundation. Specifically, the waterproof layer 6 can be a high-density polyethylene geomembrane, and can be replaced with a composite geomembrane or a rubber waterproof membrane to ensure excellent tensile strength and absolute impermeability.

[0026] The composite capillary layer 5 is made of silty clay or modified clay as the main material, and mixed with silt, fine sand, stone powder or fine aggregate to form a dense composite mixture. It is continuously laid along the micro-arched waterproof layer 6. The composite mixture is spread and compacted to reduce soil permeability and water vapor migration rate.

[0027] By employing a water-resistant layer 6 and a composite capillary barrier layer 5 to form a micro-arched barrier structure, the composite capillary barrier layer 5 is a well-graded and dense mixture of silty clay improved material and silt or fine sand. Together with the water-resistant layer 6, it forms a composite, dense, low-permeability and air-permeable micro-arched seepage prevention and barrier, effectively cutting off the upward migration channels of underground liquid water and water vapor, and preventing the intrusion and damage of groundwater level rise to the upper roadbed.

[0028] The drainage transition layer 4 uses graded crushed stone or coarse sand with a large pore structure as a highly permeable substrate, and is laid and compacted in layers. The drainage transition layer 4 is continuously laid on the upper surface of the composite capillary layer 5 to provide ample large pore channels as lateral drainage channels for discharging residual water vapor and stagnant water inside the roadbed.

[0029] The damping transition layer 3 is paved with elastic damping materials, which are polyurethane-based elastic materials or high-damping modified asphalt mixtures. The damping transition layer 3 is laid close to the guide transition layer 4. The polyurethane-based elastic material is polyurethane elastomer or polyurethane-rubber particle composite material, which utilizes its high damping characteristics to efficiently absorb and dissipate the vibration energy generated by traffic loads.

[0030] A vibration-damping transition layer 3 is set below the road base layer 2 to weaken the transmission of vehicle cyclic load and vibration to the lower fill and water migration channels. It suppresses the dynamic effect of vibration on capillary water rise from the source, and achieves coordinated prevention and control of vibration reduction, isolation and strong drainage. Through the coordinated layout of materials and structure, it simultaneously meets the engineering requirements of groundwater isolation, active regulation and vibration reduction to suppress capillary rise in thick fill areas. It effectively suppresses roadbed wetting and softening, pavement cracking and settlement and heave, and has stronger engineering applicability.

[0031] The seepage ditch 8 is made of highly permeable materials, including no-fines concrete, no-fines large-pore crushed stone, or graded gravel.

[0032] In this embodiment, a left-side culvert 7 and a right-side culvert 7 are constructed in shallow trenches on both sides of the ground surface, with the bottom of the right-side culvert 7 being deeper than that of the left-side culvert 7. A base seepage trench 8 with extremely high permeability is formed by backfilling sand-free, large-pore gravel and other highly permeable materials in the deep seepage trench directly below the left-side culvert 7.

[0033] The upper surface of the culvert 7 has several water inlet holes to allow surface water to flow in. The soil-facing sidewall of the culvert 7 has several seepage holes. The seepage holes are connected to the drainage transition layer 4 and the shock-absorbing transition layer 3 to collect interlayer water. The seepage holes are covered with reverse filter geotextile or a crushed stone reverse filter layer to intercept soil particles and allow water to seep into the culvert.

[0034] The deep side culvert 7 is equipped with a confluence hole located below the waterproof layer 6, so that the water blocked by the waterproof layer 6 can be diverted into the deep side culvert 7. An asymmetrical lateral drainage structure is constructed on both sides of the road. The bottom surface of the shallow side culvert 7 is provided with a vertical connecting hole that connects with the seepage ditch 8 below. The shallow side culvert 7 and the base seepage ditch 8 are stacked one on top of the other. The side wall of the deep side culvert 7 is also provided with a water outlet hole that connects with the collection well 10. The deep side culvert 7 and the collection well 10 are arranged side by side to form a three-dimensional diversion and drainage system.

[0035] By utilizing the slightly arched slope of the impermeable layer 6, the groundwater and the capillary water that has been blocked and condensed are laterally diverted to both sides. The water flow on the left side is discharged into the seepage ditch 8 on the left side of the foundation, and the water flow on the right side is directly discharged into the deepened right side culvert 7. The upper stagnant water is promptly guided into the culvert 7 through the drainage transition layer 4, realizing the combined effect of blocking and lateral diversion, avoiding the accumulation of water in the core area of ​​the roadbed, and forming a proactive defense mechanism of "blocking-drainage" synergy.

[0036] It also includes: a water level monitoring device 12, which is installed in the water collection well 10 to monitor the water level in the water collection well 10. The water level monitoring device 12 is electrically connected to the PLC controller. The water level monitoring device 12 collects groundwater level information in real time and transmits it to the PLC controller. The drain pipe 11 is connected at one end to the water pump 9 and at the other end to the outside of the water collection well 10. The water pump 9 is suspended at the bottom of the water collection well 10 and is electrically connected to the PLC controller. The specifications and depth of the water collection well 10 can be flexibly adjusted according to the measured groundwater recharge and the head and flow parameters of the water pump 9. When the water level is higher than the upper limit threshold, the PLC controller outputs a command to start the water pump 9. The water pump 9 pumps water out of the collection well 10 through the drain pipe 11. When the water level is lower than or equal to the lower limit threshold, the PLC controller controls the water pump 9 to stop running.

[0037] The unified and forceful drainage by pump 9 effectively protects the stability of the core area of ​​the roadbed. At the same time, the water level monitoring device 12 automatically implements drainage regulation according to changes in the groundwater level, realizing dynamic and proactive regulation of the groundwater level. This overcomes the lag of traditional static isolation or conventional drainage and enhances the proactive prevention and control capabilities against the continuous rise of the groundwater level in thick fill areas.

[0038] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A method for preventing surface deformation caused by groundwater level rise in thick fill areas, characterized in that, Includes the following steps: S1: Excavate longitudinal underground ditches (7) on both sides of the main roadbed. The underground ditches (7) on both sides are arranged in an asymmetrical depth. Excavate a seepage ditch (8) below the shallow underground ditch (7) and excavate a water collection well (10) on one side of the deep underground ditch (7). S2: An arched waterproof layer (6) is laid on the subgrade layer. A composite capillary barrier layer (5), a drainage transition layer (4), a shock-absorbing transition layer (3), and a roadbed layer (2) are laid sequentially on the upper surface of the waterproof layer (6). S3: The water collected by the drainage transition layer (4) is discharged into the underground ditch (7) on both sides. The water blocked by the water-proof layer (6) is introduced into the infiltration ditch (8) and the deep side underground ditch (7). The water collected by the deep side underground ditch (7) is introduced into the water collection well (10). The water collected by the shallow side underground ditch (7) and the infiltration ditch (8) is discharged naturally along the longitudinal direction of the road. S4: Install a water pump (9) in the water collection well (10). When the water level is higher than the upper limit threshold, the water pump (9) pumps out the water in the water collection well (10).

2. The method for preventing surface deformation caused by groundwater level rise in thick fill areas according to claim 1, characterized in that, In S1, the main body of the roadbed is leveled, rolled and compacted, sharp stones on the surface are removed, and an arched transverse slope foundation with a high middle and low sides is rolled out. At the same time, a ditch is dug on both sides (7).

3. The method for preventing surface deformation caused by groundwater level rise in thick fill areas according to claim 1, characterized in that, The waterproof layer (6) is made of a highly durable flexible impermeable material.

4. The method for preventing surface deformation caused by groundwater level rise in thick fill areas according to claim 1, characterized in that, The composite capillary layer (5) is made of silty clay or modified clay as the main material, and mixed with silt or fine sand to form a dense composite mixture.

5. The method for preventing surface deformation caused by groundwater level rise in thick fill areas according to claim 1, characterized in that, The guide transition layer (4) uses graded crushed stone or coarse sand with large pore structure as a highly permeable substrate, and is laid and compacted in layers.

6. The method for preventing surface deformation caused by groundwater level rise in thick fill areas according to claim 1, characterized in that, The damping transition layer (3) is paved with elastic damping materials.

7. The method for preventing surface deformation caused by groundwater level rise in thick fill areas according to claim 1, characterized in that, The seepage trench (8) is made of highly permeable material.

8. The method for preventing surface deformation caused by groundwater level rise in thick fill areas according to claim 1, characterized in that, In S2, the roadbed (2) is covered with a pavement layer (1).

9. The method for preventing surface deformation caused by groundwater level rise in thick fill areas according to claim 1, characterized in that, The deep side culvert (7) is provided with a confluence hole, which is located below the waterproof layer (6) so that the water blocked by the waterproof layer (6) can be introduced into the deep side culvert (7).

10. The method for preventing surface deformation caused by groundwater level rise in thick fill areas according to claim 1, characterized in that, Also includes: A water level monitoring device (12) is used to monitor the water level in the collection well (10); The drain pipe (11) is connected at one end to the water pump (9) and at the other end extends to the outside of the collection well (10); When the water level is higher than the upper limit threshold, the water pump (9) pumps water out of the collection well (10) through the drain pipe (11). When the water level is lower than or equal to the lower limit threshold, the water pump (9) stops.

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