Treatment method for high-water-level non-uniform foundation in water-rich area

Abstract

The invention relates to the technical field of foundation treatment, in particular to a treatment method for a high-water-level non-uniform foundation in a water-rich area. The construction method comprises the steps of 1, laying a cushion layer on the surface layer of a treatment area, 2, carrying out first-time point tamping construction, 3, carrying out second-time point tamping construction, 4, carrying out third-time full tamping construction, 5, laying geotechnical cloth in a water-rich area, 6, laying geotechnical cloth at the lap joint of a new runway pavement and an old runway pavement, and 7, arranging a blind ditch. The situation of fine particle loss can be reduced by laying the geotechnical cloth, the possibility of differential settlement is reduced, differential settlement of the foundation is reduced, the bearing capacity of the foundation is enhanced, and different foundation treatment modes are adopted for different foundation problems; and construction technology and process parameters suitable for the foundation stability and drainage problem of the water-rich area are formed.

Description

Technical Field

[0001] The present application relates to the technical field of foundation treatment, and in particular to a method for treating uneven foundation with high water level in a water-rich area. Background Art

[0002] In recent years, the demand for air transportation in Tibet has continued to grow. In order to improve the airport's capacity, efficiency and safety assurance capabilities, it is necessary to build a second runway at a high plateau airport. Compared with other plain airports, high plateau airports are located in areas with complex terrain, groundwater levels, harsh environmental conditions, and variable climate changes, making airport foundation treatment more difficult. Especially in water-rich areas, the content of medium and coarse particles is large and low, with pores as storage space and migration channels. Its permeability and water richness are mainly controlled by the particle size, gradation and content of medium and coarse particles of loose deposits. Therefore, a foundation treatment method is needed to solve the problems of foundation liquefaction and uneven foundation settlement. Summary of the invention

[0003] In order to reduce uneven settlement of the foundation and enhance the bearing capacity of the foundation, the present application provides a method for treating uneven foundation with high water level in a water-rich area.

[0004] The above technical objectives of this application are achieved through the following technical solutions: A method for treating uneven foundation with high water level in a water-rich area, comprising: Step 1: Lay a cushion layer on the surface of the treatment area; Step 2: First time of spot tamping construction; Step 3: Second time of spot tamping construction; Step 4: The third full tamping construction; Step 5: Lay geotextile in water-rich areas; Step 6: Lay geotextile at the joint of the new and old runway surfaces; Step 7: Set up blind ditch.

[0005] By adopting the above technical scheme, the strong compaction of the cushion layer can form a stress diffusion layer, which is beneficial to the propagation of the tamping energy, so that the tamping energy can be more effectively transmitted to the deep foundation, thereby improving the density and bearing capacity of the soil and improving the strong compaction effect. The full compaction construction after the strong compaction of the cushion layer can solve the problem of foundation bearing capacity and can compact and squeeze the foundation. A suitable treatment scheme and process parameters are formed to achieve a standard penetration number of >4 hits without liquefaction, thereby enhancing the foundation bearing capacity. The laying of geotextiles on the treated foundation can reduce the loss of fine particles and reduce the possibility of uneven settlement, thereby reducing the ground The uneven settlement of the foundation can enhance the bearing capacity of the foundation, enhance the integrity and continuity of the foundation, improve the durability and safety of the foundation. The setting of blind ditches can effectively drain groundwater, lower the groundwater level, reduce the risk of foundation softening, reduce uneven settlement of the foundation, improve the stability of the foundation, and reduce the water pressure on the foundation. The newly built second runway area can drain precipitation through the blind ditch when the water level is below the normal level, solve the drainage problem in water-rich areas, save operating costs, and adopt different foundation treatment methods for different foundation problems to form construction technology and process parameters suitable for foundation stability and drainage problems in water-rich areas.

[0006] Optionally, the cushion layer in step 1 is paved with medium-weathered sandstone excavation material, and the cushion layer is paved with a thickness of 1 to 1.5 m; The filling materials in step 2 and step 3 are excavated materials of medium-weathered sandstone and sandy slate.

[0007] By adopting the above technical scheme, the cushion layer is paved with medium-weathered sandstone excavation materials, which can increase the distance between the groundwater level and the ground surface, reduce the possibility of slurry overflow in the ramming pit, and facilitate the subsequent strong ramming construction. After the strong ramming construction, it is beneficial to the settlement stability of the foundation and the improvement of the foundation strength, and can promote the discharge of water in the soft soil layer, reduce the settlement of the shallow part of the foundation, and improve the overall stability of the foundation. The filling material is made of medium-weathered sandstone and sandy slate excavation materials, which can improve the bearing capacity of the foundation, enhance the stability and bearing capacity of the foundation, and reduce the risk of foundation liquefaction. The medium-weathered sandstone and sandy slate excavation materials have good water permeability, can reduce the settlement of the foundation, ensure the stability and bearing capacity of the foundation, and reduce the later maintenance and repair costs of the foundation.

[0008] Optionally, in the flooded waterlogged area of ​​the water-rich area in step 5, at least two layers of geotextiles are laid after the original foundation is treated; In step 6, the geotextile is laid at the joint of the new and old runway surfaces 0.5m below the top surface of the roadbed; The geotextile has no joints along its entire length in the main stress-bearing direction, and the overlap length in the non-main stress-bearing direction shall not be less than 15cm.

[0009] By adopting the above technical solution and using different geotextile laying methods on different foundations, it is possible to reduce the loss of fine particles, maintain the stability and integrity of the foundation treatment layer, reduce the risk of damage to the foundation by external factors, and reduce the possibility of uneven settlement. Laying geotextiles under the top surface of the subgrade at the junction of the new and old runways can enhance the integrity and continuity of the foundation, improve the durability and safety of the foundation, and extend the service life of the foundation and superstructure.

[0010] Optionally, when laying the geotextile, a fixing device is used to fix it to the surface of the fill layer. The fixing device includes a fixing plate, which is fixedly connected to a fixing frame. The fixing plate is provided with sliding holes. There are at least two sliding holes, and both sliding holes are inclined. Pins are inserted into the sliding holes, and one end of the pin is processed to form a baffle.

[0011] By adopting the above technical solution, the stability of the fixing device in the fill layer can be increased, ensuring that the geotextile can be firmly fixed on the surface of the fill layer.

[0012] Optionally, a sleeve is provided on the peripheral wall of the pin, an anti-slip block is integrally formed on the peripheral wall of the sleeve, and a plurality of anti-slip blocks are arranged at intervals.

[0013] By adopting the above technical solution, the sleeve can pass through the sliding hole along with the nail, and the anti-slip block is deformed and slides along the sliding wall when passing through the sliding hole. The sleeve returns to its original state after passing through the sliding hole, which can prevent the sleeve and the nail from falling out of the fill layer, ensuring that the geotextile can be firmly fixed on the surface of the fill layer.

[0014] Optionally, a pressure strip is integrally formed on the fixing frame, a plurality of pressure strips are arranged at intervals, and one side of the pressure strip is processed to form a curved surface.

[0015] By adopting the above technical solution, the pressure strip can increase the friction between the fixing frame and the geotextile, ensure that the pressure strip can be pressed tightly on the geotextile, and ensure that the geotextile can be firmly fixed on the surface of the fill layer. The curved surface of the pressure strip can reduce the risk of damage to the geotextile when the fixing device is pressed tightly on the geotextile, thereby ensuring the stability and durability of the geotextile in the project.

[0016] Optionally, a prefabricated drainage pipe is used when setting up the blind ditch. The prefabricated drainage pipe includes a base, a pipe body is integrally formed on the base, reinforcing ribs are formed on the peripheral wall of the pipe body, a first water filter layer is bonded to the peripheral wall of the pipe body, and water seepage holes are opened on the peripheral wall of the pipe body.

[0017] By adopting the above technical solution, the base is convenient for placing the prefabricated drainage pipe in a flat foundation pit, and the spirally arranged reinforcement ribs can increase the overall structural strength of the pipe body, while reducing the pressure of the soil load on the first water filter layer and the seepage holes, ensuring that the first water filter layer and the seepage holes can filter groundwater. The groundwater will penetrate into the first water filter layer on the peripheral wall of the pipe body through the permeable geotextile, and then flow into the interior of the pipe body through the seepage holes after being filtered by the first water filter layer. The internal space of the pipe body is large, which can improve the drainage efficiency of the blind ditch, lower the groundwater level, reduce the risk of foundation softening, reduce uneven foundation settlement, improve the stability of the foundation, and reduce the water pressure on the foundation. The prefabricated drainage pipe can simplify the blind ditch construction steps, which is conducive to shortening the blind ditch construction period.

[0018] Optionally, a reinforcing plate is integrally formed in the tube body, a connecting plate is connected between the reinforcing plate and the tube body, and a water-permeable hole is formed on the reinforcing plate.

[0019] By adopting the above technical solution, the outer wall of the pipe body mainly bears the load of the external soil. The pipe body is easily damaged under greater pressure. The reinforcing plate and the connecting plate are connected to the pipe body, which can increase the structural strength of the pipe body, increase the overall structural strength of the prefabricated drainage pipe, and increase the service life of the blind ditch.

[0020] Optionally, a second water filter layer is bonded to the reinforcing plate.

[0021] By adopting the above technical solution, when the permeable geotextile and the first water filter layer are damaged under greater pressure, groundwater flows into the pipe body from the seepage holes, can flow through the second water filter layer and filter out impurities, ensuring that the pipe body is not polluted or even blocked, ensuring the drainage efficiency of the blind ditch, and increasing the service life of the blind ditch.

[0022] Optionally, a connecting pipe head is slidably provided at one end of the tube body, the outer diameter of one end of the connecting pipe head is smaller than the inner diameter of the tube body, a connecting block is fixedly connected to the connecting pipe head, a hanging ring is fixedly connected to the connecting block, and a connecting pipe seat is provided at the other end of the tube body, the inner diameter of one end of the connecting pipe seat is larger than the outer diameter of one end of the connecting pipe head, and a movable opening is opened on the connecting pipe seat for sliding the connecting block.

[0023] By adopting the above technical solution, the lifting ring is pulled to make the connecting pipe head slide out of the pipe body and inserted into the adjacent connecting pipe seat, so that the connecting block slides in the movable opening of the adjacent connecting pipe seat. The staff can observe the connection status of the connecting pipe head and the connecting pipe seat through the movable opening. The outer diameter of the connecting pipe head is smaller than the inner diameter of the connecting pipe seat, which is convenient for connecting the two adjacent prefabricated drainage pipes end to end in the blind ditch foundation pit.

[0024] In summary, this application has the following technical effects: 1. Through the replacement of cushion layer, strong tamping and full tamping, a suitable treatment scheme and process parameters are formed, achieving a standard penetration number of more than 4 hits without liquefaction, enhancing the bearing capacity of the foundation, and forming a construction process suitable for foundation treatment with stable foundation in water-rich areas; 2. By laying geotextiles, the loss of fine particles can be reduced, the possibility of uneven settlement can be reduced, the uneven settlement of the foundation can be reduced, the possibility of uneven settlement at the connection between the new and old foundations can be reduced, and the bearing capacity of the foundation can be enhanced; 3. By setting up a fixing device, the stability of the fixing device in the fill layer can be increased, ensuring that the geotextile can be firmly fixed on the surface of the fill layer, ensuring the stability and durability of the geotextile in the project. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the appearance structure diagram of the fixing device of the present application; Figure 2 This is a structural diagram of the fixing device of the present application from another angle; Figure 3 It is the appearance structure diagram of the prefabricated drainage pipe of this application; Figure 4 It is a cross-sectional structural diagram of the prefabricated drainage pipe of the present application; Figure 5 It is another cross-sectional structural diagram of the prefabricated drainage pipe of the present application.

[0026] Explanation of the reference numerals in the accompanying drawings: 1. fixing plate; 11. sliding hole; 2. fixing frame; 21. pressure strip; 3. nail; 31. baffle; 4. sleeve; 41. anti-drop block; 5. base; 6. pipe body; 61. reinforcing rib; 62. first water filter layer; 63. seepage hole; 7. reinforcing plate; 71. connecting plate; 72. water permeable hole; 73. second water filter layer; 8. connecting pipe head; 81. connecting block; 82. lifting ring; 9. connecting pipe seat; 91. movable opening. DETAILED DESCRIPTION

[0027] The present application is further described in detail below in conjunction with the accompanying drawings.

[0028] Embodiment 1 The embodiment of the present application discloses a method for treating uneven foundation with high water level in a water-rich area. In the embodiment, taking the flight zone project of the newly built second-phase runway project of a certain airport in Tibet as an example, according to the survey report, the original flight zone of the airport is mainly located on the first-level terrace and the high floodplain of the river, the proposed second-phase runway flight zone is located on the first-level terrace-the high floodplain of the river, and most of the proposed site is located on the floodplain, the groundwater level is high, the original silt layer has a high water content, and the overall landform type belongs to river depositional landform. There are many seasonal braided rivers winding in the high floodplain site, the river width varies from 8 to 30 meters, the braided river cutting depth is 2 to 4 meters, and there are occasional small ditches excavated by humans.

[0029] Three groups of test areas were selected from areas without obvious water accumulation and areas with water accumulation for dynamic compaction test. The area of ​​each test group was about 1500-2000㎡. The areas without obvious water accumulation adopted 2000kN.m energy level cushion layer for dynamic compaction, and the areas with water accumulation adopted 3000kN.m energy level cushion layer for dynamic compaction. Different compaction intervals of 3m, 4m and 5m were adopted for dynamic compaction in the six test areas, and the best compaction interval was 4m.

[0030] Ground treatment methods include: Step 1: Lay a cushion layer with a thickness of 1 to 1.5m on the surface of the treatment area. The cushion layer thickness in areas without obvious water accumulation is 1m, and the cushion layer thickness in areas with water accumulation is 1.5m. The cushion layer thickness can be adjusted according to the on-site foundation and groundwater level.

[0031] The cushion layer is paved with medium-weathered sandstone excavation materials. The medium-weathered sandstone excavation materials are well graded, with a maximum particle size of no more than 80 cm, particles with a particle size greater than 30 cm accounting for no more than 30%, and particles with a particle size greater than 2 cm accounting for no less than 60%.

[0032] By using medium-weathered sandstone as the cushion layer, the distance between the groundwater level and the surface can be increased, the possibility of mud overflow in the ramming pit can be reduced, and it is beneficial to the subsequent strong tamping construction. During strong tamping, the cushion layer can form a stress diffusion layer, which is beneficial to the propagation of tamping energy, so that the tamping energy can be more effectively transmitted to the deep foundation, thereby improving the density and bearing capacity of the soil and improving the strong tamping effect. After the cushion layer is strongly tamped, it is beneficial to the settlement stability of the foundation and the improvement of the foundation strength, which can promote the discharge of water in the soft soil layer, reduce the settlement of the shallow part of the foundation, and improve the overall stability of the foundation.

[0033] Step 2: The first spot tamping construction is carried out. The tamping points are arranged in a 4m×4m square. When the tamping pit is too deep, fill the pit with stuff. The number of single hits is 10 to 14. The average tamping amount of the last two hits is not more than 5cm. After the first spot tamping construction, fill the pit and measure the ground elevation.

[0034] Step three, the second time of spot tamping construction, the tamping points are arranged in a 4m×4m square. When the depth of the tamping pit is too large, fill the tamping pit with stuff. The number of single hits is 9 to 11. The average tamping amount of the last two hits is not more than 5cm. After the second time of spot tamping construction, fill the tamping pit and measure the ground elevation.

[0035] The filling material is excavated medium-weathered sandstone and sandy slate with good gradation. The maximum particle size is no more than 2 / 3 of the loose paving thickness, and the content of particles larger than 2 cm is not less than 50%.

[0036] By using medium-weathered sandstone and sandy slate excavated materials as filling materials, the bearing capacity of the foundation can be improved, the stability and bearing capacity of the foundation can be enhanced, and the risk of foundation liquefaction can be reduced. The medium-weathered sandstone and sandy slate excavated materials have good water permeability, which can reduce the settlement of the foundation, ensure the stability and bearing capacity of the foundation, and reduce the later maintenance and repair costs of the foundation.

[0037] Step 4: Carry out the third full tamping construction with d / 4 overlap of tamping points and 4 to 5 single-point tappings. The average tamping settlement of the last two taps should not exceed 3 cm. After full tamping, measure the ground elevation and calculate the final average tamping settlement.

[0038] By replacing the cushion layer in the water-rich area with strong compaction and full compaction, the cushion layer virtual thickness is 1.5m. After strong compaction of the cushion layer with an energy level of 2000kN·m, the density requirement of the trench area is met. According to the standard penetration test results after strong compaction, the use of strong compaction and full compaction of the cushion layer can solve the problem of foundation bearing capacity and compact the foundation, forming a suitable treatment plan and process parameters, achieving the standard penetration number of more than 4 blows without liquefaction, enhancing the bearing capacity, and forming a construction process for foundation treatment suitable for stable foundation in water-rich areas.

[0039] Step 5: Lay geotextile in water-rich areas.

[0040] For flooded areas, two layers of high-strength woven geotextiles are laid after the original foundation is treated; For the waterlogged ditch and pond area, a layer of high-strength woven geotextile is laid after the original foundation is treated.

[0041] Step 6. At the joint of the new and old runway pavements, lay a layer of high-strength woven geotextile 0.5m below the top surface of the roadbed.

[0042] The high-strength woven geotextile has no joints in the main stress direction, and the overlap length in the non-main stress direction is not less than 15cm. The high-strength woven geotextile should be laid without wrinkles and should be tightened manually and fixed to the surface of the fill layer by means of nails and other measures.

[0043] When laying high-strength woven geotextile, the surface of the fill layer is flat without hard protrusions such as gravel and stones. Sand and pebble fillers are used for protection within 10 cm above and below the geotextile. The maximum particle size of the sand and pebble fillers is not more than 6 cm. The upper layer of sand and pebble fillers is backfilled with medium-weathered sandstone or sandy slate.

[0044] After the laying is completed, the settlement observation is carried out. The settlement of the runway after construction in the trough area is less than 20cm, and the differential settlement after construction is less than 1.0‰ in the longitudinal direction, which can meet the requirements of uneven settlement. By laying high-strength woven fabrics and using different geotextile laying methods on different foundations, the loss of fine particles can be reduced, the stability and integrity of the foundation treatment layer can be maintained, the risk of damage to the foundation by external factors can be reduced, and the possibility of uneven settlement can be reduced. Laying geotextiles under the top surface of the foundation at the junction of the new and old runways can enhance the integrity and continuity of the foundation, improve the durability and safety of the foundation, and extend the service life of the foundation and superstructure.

[0045] Step 7. Set up blind ditches to drain precipitation, set up inspection wells at the bends and high and low places of the blind ditch, and set up water filter grates at the outlets of the inspection wells.

[0046] Blind ditch construction process: (1) Construction layout: Determine the starting and ending points of the blind ditch, set the longitudinal slope at the bottom of the ditch, and make the two ends straight; (2) Excavation of foundation pit: excavation is carried out by excavator, and the longitudinal slope of the bottom of the ditch is trimmed manually. The foundation pit is inspected and accepted by the supervision engineer; (3) Geotextile laying: Before laying the geotextile, manually check and level the foundation pit, and lay the permeable geotextile as required; (4) Gravel backfill: The backfill should be laid in layers by manual labor and excavators. The appearance of the backfill should be neat and smooth, and the plane geometric dimensions should meet the specifications and design requirements.

[0047] The blind ditch can effectively drain groundwater through its internal coarse-grained material and inverted filter layer structure, lower the groundwater level, reduce the risk of foundation softening, reduce uneven foundation settlement, improve the stability of the foundation, and reduce the water pressure on the foundation. Through the inspection well, the changes in the groundwater level can be monitored in real time, providing important data support for foundation treatment. By setting up a blind ditch, the newly built second runway area can drain precipitation through the blind ditch by gravity when the water level is below the normal level, solving the problem of drainage in water-rich areas and saving operating costs.

[0048] Embodiment 2 The difference between this embodiment and the first embodiment is that: When laying the high-strength woven geotextile in step 2, it is tightened manually and then fixed to the surface of the fill layer by a fixing device.

[0049] Reference Figure 1 and Figure 2The fixing device includes a fixing plate 1, the surface of the fixing plate 1 is rectangular, a fixing frame 2 is welded to the edge of the fixing plate 1, a sliding hole 11 is opened on the fixing plate 1, two sliding holes 11 are opened on the fixing plate 1 at intervals, the opening directions of the two sliding holes 11 are inclined to the surface direction of the fixing plate 1, and the inclination directions of the opening directions of the two sliding holes 11 are opposite, a pin 3 is penetrated in the sliding hole 11, the pin 3 slides in the sliding hole 11, and a baffle 31 is formed at one end of the pin 3 away from the tip, and the surface of the baffle 31 is parallel to the surface of the fixing plate 1.

[0050] When using the fixing device, the staff places the fixing plate 1 on the surface of the geotextile to be fixed, and one side of the fixing plate 1 and the fixing frame 2 fits with the geotextile. The staff presses the baffle 31 to move it toward the geotextile, driving the pins 3 to pass through the geotextile and insert into the fill layer. After the two pins 3 with opposite inclined directions are inserted into the fill layer, the stability of the fixing device in the fill layer can be increased, ensuring that the geotextile can be firmly fixed on the surface of the fill layer.

[0051] Reference Figure 1 and Figure 2 , a sleeve 4 is sleeved at a section of the pin 3 away from the tip, the sleeve 4 is made of elastic plastic, and an anti-slip block 41 is integrally formed on the peripheral wall of the sleeve 4. The anti-slip block 41 is in a strip shape and its length direction is inclined to the end of the pin 3 away from the tip, and a plurality of anti-slip blocks 41 are arranged at intervals along the length direction of the sleeve 4. When the pin 3 slides in the sliding hole 11, the sleeve 4 can pass through the sliding hole 11 along with the pin 3, and at the same time, the anti-slip block 41 is deformed and slides along the sliding peripheral wall when passing through the sliding hole 11. After the sleeve 4 passes through the sliding hole 11, it returns to its original state, which can prevent the sleeve 4 and the pin 3 from falling out of the fill layer, and ensure that the geotextile can be firmly fixed on the surface of the fill layer.

[0052] Reference Figure 1 and Figure 2 The side of the fixing frame 2 facing the geotextile is integrally formed with a pressure strip 21, and a plurality of pressure strips 21 are arranged at intervals along the length direction of the fixing frame 2, and the pressure strips 21 are arc-shaped on the side facing the geotextile. When the fixing frame 2 contacts the geotextile, the pressure strip 21 can increase the friction between the fixing frame 2 and the geotextile, and the arc surface of the pressure strip 21 can reduce the risk of damage caused by the fixing device pressing on the geotextile.

[0053] Prefabricated drainage pipes are used in the blind ditch construction process of step seven: Reference Figure 3 and Figure 4The prefabricated drainage pipe includes a base 5, on which a pipe body 6 is integrally formed, and a peripheral wall of the pipe body 6 is processed to form a reinforcing rib 61, which is spirally arranged along the peripheral wall of the pipe body 6, and a first water filter layer 62 is bonded to the peripheral wall of the pipe body 6, and the first water filter layer 62 is arranged along the gap between the reinforcing ribs 61, and the first water filter layer 62 is in contact with the side wall of the reinforcing rib 61, and a water seepage hole 63 is opened on the peripheral wall of the pipe body 6, and a plurality of water seepage holes 63 are spaced apart along the peripheral wall of the pipe body 6, and the water seepage holes 63 and the first water filter layer 62 are opened correspondingly, and the water seepage holes 63 and the reinforcing rib 61 are staggered.

[0054] During the construction of the blind ditch, after the permeable geotextile is laid in the foundation pit, the prefabricated drainage pipe is placed in the foundation pit to replace the gravel backfill. The base 5 can increase the stability of the prefabricated drainage pipe in the foundation pit, making it easier to place the prefabricated drainage pipe in a flat foundation pit. The spirally arranged reinforcing ribs 61 can increase the overall structural strength of the pipe body 6, while reducing the pressure of the soil load on the first water filter layer 62 and the seepage holes 63, ensuring that the first water filter layer 62 and the seepage holes 63 can filter groundwater. The groundwater will penetrate into the first water filter layer 62 on the peripheral wall of the pipe body 6 through the permeable geotextile, and then flow into the interior of the pipe body 6 through the seepage holes 63 after being filtered by the first water filter layer 62. The internal space of the pipe body 6 is relatively large, which can improve the drainage efficiency of the blind ditch, lower the groundwater level, reduce the risk of foundation softening, reduce uneven foundation settlement, improve the stability of the foundation, and reduce the water pressure on the foundation. The prefabricated drainage pipe can simplify the blind ditch construction steps and help shorten the blind ditch construction period.

[0055] Reference Figure 4 and Figure 5 A reinforcing plate 7 is integrally formed in the tube body 6. The plate surface of the reinforcing plate 7 is arched and is arranged along the length direction of the tube body 6. A connecting plate 71 is integrally formed between the side of the reinforcing plate 7 away from the base 5 and the inner wall of the tube body 6. The connecting plate 71 is arranged along the length direction of the tube body 6 and a plurality of connecting plates 71 are arranged at intervals along the plate surface of the reinforcing plate 7. A plurality of water-permeable holes 72 are arranged at intervals on the plate surface of the reinforcing plate 7. A second water filter layer 73 is bonded to the plate surface of the reinforcing plate 7 on the side away from the base 5.

[0056] The prefabricated drainage pipe is buried in the blind ditch foundation pit. Since the outer wall of the pipe body 6 mainly bears the load of the external soil, the pipe body 6, the permeable geotextile and the first water filter layer 62 are easily damaged under greater pressure. When groundwater flows into the pipe body 6 from the seepage hole 63, it can flow through the second water filter layer 73 and filter out impurities, ensuring that the pipe body 6 is not polluted or even blocked, ensuring the drainage efficiency of the blind ditch, and increasing the service life of the blind ditch. At the same time, the reinforcing plate 7 and the connecting plate 71 are connected to the pipe body 6, which can increase the structural strength of the pipe body 6 and increase the overall structural strength of the prefabricated drainage pipe.

[0057] Reference Figure 5A connecting pipe head 8 is slidably provided at one end of the tube body 6, and the outer diameter of the end of the connecting pipe head 8 away from the tube body 6 is smaller than the inner diameter of the tube body 6. A section of the connecting pipe head 8 away from the tube body 6 is fixedly connected to a connecting block 81 by bolts, and a hanging ring 82 is fixedly connected to the connecting block 81 by bolts. A connecting pipe seat 9 is provided at the other end of the tube body 6, and the inner diameter of the end of the connecting pipe seat 9 away from the tube body 6 is larger than the outer diameter of the end of the connecting pipe head 8 away from the tube body 6. A section of the connecting pipe seat 9 away from the tube body 6 is provided with a movable opening 91 that matches the connecting block 81, and the connecting block 81 can slide in the movable opening 91.

[0058] When laying prefabricated drainage pipes, the workers place the prefabricated drainage pipes in sequence in the foundation pit so that one end of the prefabricated drainage pipe provided with the connecting pipe head 8 is opposite to the end of the adjacent prefabricated drainage pipe provided with the connecting pipe seat 9, and pull the lifting ring 82 to make the connecting pipe head 8 slide out of the pipe body 6 and insert it into the adjacent connecting pipe seat 9, so that the connecting block 81 slides in the movable opening 91 of the adjacent connecting pipe seat 9. The workers can observe the connection status of the connecting pipe head 8 and the connecting pipe seat 9 through the movable opening 91. The outer diameter of the connecting pipe head 8 is smaller than the inner diameter of the connecting pipe seat 9, which is convenient for connecting the two adjacent prefabricated drainage pipes end to end in the blind ditch foundation pit.

[0059] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for treating uneven foundation with high water level in a water-rich area, characterized by: Ground treatment methods include: Step 1: Lay a cushion layer on the surface of the treatment area; Step 2: First time of spot tamping construction; Step 3: Second time of spot tamping construction; Step 4: The third full tamping construction; Step 5: Lay geotextile in water-rich areas; Step 6: Lay geotextile at the joint of the new and old runway surfaces; Step 7: Set up blind ditch.

2. A method for treating uneven foundation with high water level in a water-rich area according to claim 1, characterized in that: The cushion layer in step 1 is paved with medium-weathered sandstone excavation material, and the cushion layer is paved with a thickness of 1 to 1.5 m; The filling materials in step 2 and step 3 are excavated materials of medium-weathered sandstone and sandy slate.

3. A method for treating uneven foundation with high water level in a water-rich area according to claim 2, characterized in that: In the flooded areas of the water-rich areas in step 5, at least 2 layers of geotextiles shall be laid after the original foundation treatment; In step 6, the geotextile is laid at the joint of the new and old runway surfaces 0.5m below the top surface of the roadbed; The geotextile has no joints along its entire length in the main stress-bearing direction, and the overlap length in the non-main stress-bearing direction shall not be less than 15cm.

4. The method for treating uneven foundation with high water level in a water-rich area according to claim 1, characterized in that: When laying the geotextile, a fixing device is used to fix it on the surface of the fill layer. The fixing device comprises a fixing plate (1). The fixing plate (1) is fixedly connected to a fixing frame (2). The fixing plate (1) is provided with a sliding hole (11). There are at least two sliding holes (11), and both sliding holes (11) are inclined. A pin (3) is inserted into the sliding hole (11), and one end of the pin (3) is processed to form a baffle (31).

5. A method for treating uneven foundation with high water level in a water-rich area according to claim 4, characterized in that: The peripheral wall of the inserting pin (3) is sleeved with a sleeve (4), and the peripheral wall of the sleeve (4) is integrally formed with an anti-slip block (41), and a plurality of the anti-slip blocks (41) are arranged at intervals.

6. A method for treating uneven foundation with high water level in a water-rich area according to claim 5, characterized in that: A pressure strip (21) is integrally formed on the fixing frame (2), a plurality of pressure strips (21) are arranged at intervals, and one side of the pressure strip (21) is processed to form a curved surface.

7. The method for treating uneven foundation with high water level in a water-rich area according to claim 1, characterized in that: When setting the blind ditch, a prefabricated drainage pipe is used. The prefabricated drainage pipe comprises a base (5), a pipe body (6) is integrally formed on the base (5), a peripheral wall of the pipe body (6) is processed to form a reinforcing rib (61), a first water filter layer (62) is bonded to the peripheral wall of the pipe body (6), and a water seepage hole (63) is opened on the peripheral wall of the pipe body (6).

8. A method for treating uneven foundation with high water level in a water-rich area according to claim 7, characterized in that: A reinforcing plate (7) is integrally formed in the tube body (6), a connecting plate (71) is connected between the reinforcing plate (7) and the tube body (6), and a water-permeable hole (72) is provided on the reinforcing plate (7).

9. A method for treating uneven foundation with high water level in a water-rich area according to claim 8, characterized in that: A second water filter layer (73) is bonded onto the reinforcing plate (7).

10. A method for treating uneven foundation with high water level in a water-rich area according to claim 9, characterized in that: A connecting pipe head (8) is slidably provided at one end of the pipe body (6), the outer diameter of one end of the connecting pipe head (8) is smaller than the inner diameter of the pipe body (6), a connecting block (81) is fixedly connected to the connecting pipe head (8), a hanging ring (82) is fixedly connected to the connecting block (81), a connecting pipe seat (9) is provided at the other end of the pipe body (6), the inner diameter of one end of the connecting pipe seat (9) is larger than the outer diameter of one end of the connecting pipe head (8), and a movable opening (91) is provided on the connecting pipe seat (9) for sliding with the connecting block (81).

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