Anti-settlement construction method for soft soil roadbed of expressway

Abstract

The invention relates to the technical field of subgrade settlement prevention, in particular to an anti-settlement construction method for a soft soil subgrade of an expressway, which comprises the following steps of: burying a plurality of rows of reinforcing pile structures in the road extension direction of a soft soil subgrade section; reinforcing slurry is injected into a gap between the reinforcing pile structure and the soil layer of the soft soil roadbed section; arranging a reinforced concrete integral plate at the top of the multi-row reinforcing pile structure, and connecting the reinforced concrete integral plate with the multi-row reinforcing pile structure. The multiple rows of reinforcing pile structures are embedded in the soft soil roadbed section, so that the bearing capacity and stability of the roadbed can be effectively enhanced, and settlement and deformation of the roadbed are prevented; reinforcing slurry is injected into the gap between the reinforcing pile structure and the soil layer of the soft soil roadbed section, so that the compactness and the integrity of the soil layer can be further improved, and the compressibility and the permeability of soft soil are reduced; and the reinforced concrete integral plate is arranged at the top of the multi-row reinforcing pile structure, so that the vehicle load can be further dispersed, and local settlement is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of roadbed anti-settlement, and more specifically to an anti-settlement construction method for soft soil roadbed of expressway. Background Art

[0002] The roadbed is the foundation of the track or road surface, and is a geotechnical structure formed by excavation or filling. The main function of the roadbed is to provide the necessary conditions for track or road surface laying and train or vehicle operation, and to bear the static and dynamic loads of the track and locomotive vehicles or road surface and traffic loads, while transmitting and diffusing the loads deep into the foundation. In the longitudinal section, the roadbed must ensure the required elevation of the line; in the plane, the roadbed is connected with bridges and tunnels to form a complete through line. The roadbed is a geotechnical structure that is often invaded and damaged by changes in natural conditions such as geology, water, rainfall, climate, and earthquakes, and has poor resistance.

[0003] Soft soil roadbed refers to a common type of roadbed in special areas, which requires special design and treatment; it is mostly distributed in rivers, rivers, ocean coasts, inland lakes, ponds, basins and rainy mountain depressions. Since soft soil has the characteristics of high water content, poor permeability, low natural strength and high compressibility, it often causes uneven settlement of the roadbed, posing certain hidden dangers to driving safety. Common treatment methods for soft soil roadbeds in the prior art include base surface reinforcement, soil replacement and soil solidifier method, but the above methods are generally effective in preventing the settlement of soft soil roadbeds, and the maintenance time is short, making it difficult to achieve the ideal effect. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an anti-settling construction method for soft soil roadbed of expressways.

[0005] The technical solution adopted by the present invention is:

[0006] A method for preventing subsidence of a soft soil roadbed of a highway, the method comprising the following steps:

[0007] Multiple rows of reinforcement pile structures are buried in the road extension direction of the soft soil roadbed section;

[0008] Inject reinforcement slurry between the gap between the reinforcement pile structure and the soil layer of the soft soil roadbed section;

[0009] A reinforced concrete integral slab is arranged on the top of the multiple rows of reinforced pile structures, and the reinforced concrete integral slab is connected to the multiple rows of reinforced pile structures.

[0010] Furthermore, burying multiple rows of reinforcement pile structures in the road extension direction of the soft soil roadbed section includes:

[0011] The soft soil roadbed section is surveyed and laid out and drilled to obtain holes, into which reinforcement pile structures are inserted.

[0012] Furthermore, the reinforcement pile structure includes: a steel flower pipe for inserting into the hole.

[0013] Furthermore, surveying and setting out are performed on the soft soil roadbed section, and drilling is performed to obtain holes, and a reinforcement pile structure is inserted into the holes, including:

[0014] According to the requirements of the steel pipe grouting construction process, draw the grouting pile position map, and use the total station to measure the hole position and ground elevation, as well as the hole size and position, and mark them;

[0015] According to the drilling requirements, select a suitable drilling machine, put the drilling machine in place according to the marked position of the hole, and perform drilling to obtain the hole;

[0016] Insert the steel flower tube to the bottom of the hole and make it vertical in the middle of the hole;

[0017] Place the upper cover of the steel flower pipe on the top of the steel flower pipe.

[0018] Furthermore, the steel flower pipe is made of hot-rolled seamless steel pipe, the joints of the steel flower pipe are extended by steel sleeves, and a sealing steel plate with a diameter equal to the outer diameter of the steel flower pipe is welded to the bottom of the steel flower pipe.

[0019] Furthermore, the diameter of the steel flower tube is 89 mm, the tube wall thickness of the steel flower tube is 4.5 mm; and the diameter of the hole is 180 mm.

[0020] Furthermore, reinforcing slurry is injected between the gap between the reinforcement pile structure and the soil layer of the soft soil roadbed section, including:

[0021] The first grouting treatment is carried out between the reinforcement pile structure and the soil layer of the soft soil roadbed section, and the casing material is injected to seal the annular space between the reinforcement pile structure and the holes of the soil layer of the soft soil roadbed section to form a cement stone body;

[0022] The cement-stone body injected for the first time is split, and a second grouting treatment is carried out in the gaps of the cement-stone body, so that the injected cement slurry diffuses around the hole and reinforces the soil around the hole.

[0023] Furthermore, in the casing material injected during the first grouting treatment, the ratio of cement to water is 1:0.4-0.5, and in the cement and water mixture, an early strength high-efficiency water reducing agent is added at a ratio of 1%-2% of the mixture.

[0024] Further, a first grouting treatment is performed between the reinforcement pile structure and the soil layer of the soft soil roadbed section, and a casing material is injected to seal the annular space between the reinforcement pile structure and the holes of the soil layer of the soft soil roadbed section to form a cement stone body, including:

[0025] First, the cement is transferred from the storage area to the slurry making area, and the cement and the water in the reservoir are used to make the casing material slurry according to the preset mix ratio;

[0026] The casing material slurry is injected into the gap between the reinforcement pile structure and the soil layer of the soft soil roadbed section at a grouting pressure of 0.3-0.4 MPa to close the annular space between the reinforcement pile structure and the holes in the soil layer of the soft soil roadbed section;

[0027] The bottom grouting method is adopted for grouting of casing material. The grouting pipe adopts 22mm diameter PVC pipe. The grouting pipe is fixed together with the reinforced pile structure and lowered to 30cm from the bottom of the hole for grouting. The casing material slurry flushes the valve sleeve at the end of the grouting pipe. The grouting is carried out until grouting emerges from the hole mouth to fill the gap between the reinforced pile structure and the hole. During the grouting process, there is no casing material slurry in the reinforced pile structure. After the casing material slurry reaches the top of the reinforced pile structure, the first grouting is terminated. The casing material slurry forms a cement stone body after drying and hardening.

[0028] Further, the cement-stone body injected for the first time is split, and a second grouting treatment is performed in the gap of the cement-stone body, so that the injected cement slurry spreads around the hole to reinforce the soil around the hole, including:

[0029] After the casing material slurry dries and hardens to form a cement stone body, secondary splitting grouting is carried out. Except for the top 1.5m range of the cement stone body, splitting grouting is carried out in the rest of the range.

[0030] The secondary split grouting adopts segmented multiple split grouting, and the grouting is carried out in sections from bottom to top. The segment length of each grouting area is not more than 0.5m. Grouting is carried out using a grouting gun with grout stoppers on both the upper and lower sides;

[0031] During the secondary splitting grouting, after splitting the cement stone body of the primary grouting, the reinforced pile structure is used as the grouting pipe for the secondary splitting grouting. The cement slurry is controlled to be continuously injected at a pressure of 1.5Mpa for 5 minutes. When the amount of cement slurry for the secondary grouting reaches 150L / m, the second grouting is terminated.

[0032] It can be seen from the above scheme that the beneficial effects of the present invention are:

[0033] The invention discloses an anti-settlement construction method for a soft soil roadbed of an expressway. By burying multiple rows of reinforcement pile structures in a soft soil roadbed section, the bearing capacity and stability of the roadbed can be effectively enhanced, and settlement and deformation of the roadbed can be prevented; reinforcing slurry is injected between the gap between the reinforcement pile structure and the soil layer of the soft soil roadbed section, so that the density and integrity of the soil layer can be further improved, and the compressibility and permeability of the soft soil can be reduced; and reinforced concrete integral plates are arranged on top of the multiple rows of reinforcement pile structures, so that vehicle loads can be further dispersed, local settlement can be reduced, and the overall stability of the roadbed can be improved, so that the stability and durability of the soft soil roadbed can be effectively improved, settlement can be reduced, and driving safety and service life of the expressway can be ensured.

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0036] Figure 1 A flow chart of an anti-settlement construction method for soft soil roadbed of a highway provided by an embodiment of the present invention;

[0037] Figure 2 The cross section of the soft soil roadbed reinforcement treatment for the expressway provided by the embodiment of the present invention Figure 1 ;

[0038] Figure 3 The cross section of the reinforcement treatment of the soft soil roadbed of the expressway provided by the embodiment of the present invention Figure 2 ;

[0039] Figure 4 The plane of the soft soil roadbed of the expressway constructed by this method Figure 1 ;

[0040] Figure 5 The plane of the soft soil roadbed of the expressway constructed by this method Figure 2 ;

[0041] Figure 6 A schematic diagram of a reinforcement pile structure provided by an embodiment of the present invention;

[0042] Figure 7 A partial schematic diagram of a reinforcement pile structure provided by an embodiment of the present invention;

[0043] Figure 8 A schematic diagram of a tube body provided in an embodiment of the present invention;

[0044] Fig. 9A cross-sectional view of a tube body provided by an embodiment of the present invention;

[0045] Fig.10 A partial schematic diagram of a tube body provided in an embodiment of the present invention Figure 1 ;

[0046] Fig.11 A partial schematic diagram of a tube body provided in an embodiment of the present invention Figure 2 . DETAILED DESCRIPTION

[0047] In order to clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention, it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0049] Embodiment 1

[0050] See also Figure 1-Figure 11 The present invention provides a method for preventing subsidence of a soft soil roadbed of a highway, comprising the following steps:

[0051] Burying multiple rows of reinforcement pile structures 1 in the road extension direction of the soft soil roadbed section 3;

[0052] Injecting reinforcement slurry into the gap between the reinforcement pile structure 1 and the soil layer of the soft soil roadbed section 3;

[0053] A reinforced concrete integral slab 2 is arranged on the top of the multiple rows of reinforced pile structures 1 , and the reinforced concrete integral slab 2 is connected to the multiple rows of reinforced pile structures 1 .

[0054] The present invention provides an anti-settlement construction method for a soft soil roadbed of an expressway. By burying multiple rows of reinforcement pile structures 1 in a soft soil roadbed section 3, the bearing capacity and stability of the roadbed can be effectively enhanced to prevent the roadbed from settling and deforming. Injecting reinforcement slurry between the reinforcement pile structure 1 and the gap between the soil layer of the soft soil roadbed section 3 can further improve the density and integrity of the soil layer and reduce the compressibility and permeability of the soft soil. The dual measures of the reinforcement pile structure 1 and grouting reinforcement can significantly reduce the settlement of the roadbed and ensure the flatness and driving safety of the expressway. Arranging a reinforced concrete integral plate 2 on the top of the multiple rows of reinforcement pile structures 1 can further disperse the vehicle load. , reduce local settlement and improve the overall stability of the roadbed; the combined design of the reinforcement pile structure 1 and the reinforced concrete integral plate 3 is conducive to resisting long-term vehicle loads and the influence of the natural environment, and improving the durability of the roadbed; the reinforcement pile structure 1 can be constructed with prefabricated parts, and the on-site installation is convenient and quick, which is conducive to shortening the construction period. The grouting reinforcement technology is relatively mature, and the construction process is relatively simple and easy to operate; the anti-subsidence construction method effectively improves the stability and durability of the soft soil roadbed, reduces settlement, and ensures the driving safety and service life of the expressway through the comprehensive use of the reinforcement pile structure 1, grouting reinforcement and the reinforced concrete integral plate 2.

[0055] The reinforcement pile structure 1 includes: a steel flower pipe for inserting into the hole, the steel flower pipe is a hot-rolled seamless steel pipe, the joints of the steel flower pipe are extended by steel sleeves, and a sealing steel plate with a diameter equal to the outer diameter of the steel flower pipe is welded at the bottom of the steel flower pipe. The diameter of the steel flower pipe is 89 mm, and the wall thickness of the steel flower pipe is 4.5 mm.

[0056] The method of burying multiple rows of reinforcement pile structures 1 in the extension direction of the road of the soft soil roadbed section 3 includes: measuring and setting out and drilling on the soft soil roadbed section 3 to obtain a hole with a diameter of 180 mm, and inserting the reinforcement pile structure 1 into the hole; when drilling, according to the requirements of the steel flower pipe grouting construction process, a grouting pile position map is drawn, and the hole position and ground elevation of the hole, as well as the hole diameter size and position of the hole are measured by a total station, and marked; according to the hole diameter requirements, a suitable drilling machine is selected, and the drilling machine is put into place according to the marked position of the hole, and the drilling process is performed to obtain the hole. When drilling, the verticality of the drilling machine must meet the hole requirements, and the inclination must be controlled within the error range; the drilling error The difference deviation cannot be greater than 100mm, the inclination deviation of the hole cannot be greater than 3°, and the hole depth is not less than the design value; in order to speed up construction efficiency and reduce road milling costs, the present invention adopts an integrated down-the-hole drill, that is, a 150D crawler fully hydraulic drill. The hole depth is determined according to the thickness of the fill layer. Usually, the hole depth needs to reach the backfill layer, with a depth of 6 to 10 meters; during drilling construction: for soft foundation sections, silt and sand layers and other strata, a geological drill is used on site for drilling operations. The geological drill drills holes through high-speed rotation of the drill rod and the drill bit. When drilling, the circulating mud system of the drill rig transports flushing fluid mud and water to the bottom of the hole to cool and lubricate the drill bit, and transmits the drill cuttings in the hole to the road surface and maintains the stability of the hole wall.

[0057] According to the soil layer analysis of the hole-forming construction process of the soft soil roadbed section 3, the drilling methods in the present invention mainly include the following two categories:

[0058] Category 1: Normal soil drilling

[0059] When drilling in normal soil layers, mud and water will surge back from the hole mouth. This phenomenon can be used to determine whether there are cracks or voids in the hole and whether the hole wall is stable. This type of phenomenon is relatively simple to drill and can be done using a normal drilling rig.

[0060] After drilling to the fill layer, silt layer, sand layer, and weathered soil layer, the site needs to add a mixed liquid prepared on site for wall protection construction. The drilling mixture has the functions of suspending drill cuttings, cooling the drill bit, lubricating the drill tool, increasing the hydrostatic pressure, and forming a mud skin on the hole wall to cut off the seepage inside and outside the hole. The static pressure of the mud on the hole wall and the mud skin formed by the mud on the hole wall can effectively prevent the hole wall from collapsing. The prepared drilling mud and the mud that has been circulated and purified should determine the mud consistency according to the drilling method and the formation conditions. The mud consistency should be flexibly controlled according to the formation changes or operation requirements. If the mud is too thin, the slag removal capacity is small and the wall protection effect is poor; if the mud is too thick, it will weaken the impact function of the drill bit and reduce the drilling speed. According to calculations, the amount of mud powder used for a hole depth of 30 meters in a normal soil layer is about 3-5 bags.

[0061] Category 2: Drilling in abnormal soil layers

[0062] When drilling in abnormal soil layers, there will be no backflow at the hole mouth.

[0063] If the fill layer contains gravel, and there are situations such as hole channeling, gravel falling continuously, and drill dropping during the drilling process, stop drilling first, and use double-liquid grouting to fill the hole before drilling. Double-liquid grouting requires a double-liquid grouting machine to simultaneously deliver cement slurry and water glass. Use two PVC pipes for grouting at the same time, one for water glass and one for cement slurry. Water glass accounts for 8%-10% of the volume of cement slurry. The double-liquid grouting slurry has an adjustable gel time, which can effectively control the diffusion speed and distance of the slurry in the formation, ensuring that the flow channel of underground water is quickly blocked in the presence of underground flowing water.

[0064] When drilling without back-slurry, mud wall protection is required. The mud needs to be stirred evenly and be viscous. The amount of mud powder used for a hole depth of 30 meters in an abnormal soil layer is about 12-15 bags.

[0065] During drilling operations, if the sand layer is drilled and the hole collapses, making it impossible to form a hole, it is necessary to punch the hole. Mix the mud water or cement slurry in advance and use the circulating mud system of the drilling rig to transport it to the drill bit to fill the hole and protect the wall.

[0066] After drilling the hole, check the drilling quality, and then insert the steel pipe to the bottom of the hole, and make the steel pipe vertical in the middle of the hole; the steel pipe is made of 89×4.5mm hot-rolled seamless steel pipe on site, and the joints of multiple steel pipes are connected by steel sleeves. A 5mm thick end-sealing steel plate with a diameter equal to the outer diameter of the steel pipe is welded to the bottom of the steel pipe. After inserting the bottom of the steel pipe to the bottom of the hole, try to make the steel pipe vertical in the middle of the hole, and finally cover the upper cover of the steel pipe to prevent debris from entering the pipe and affecting the grouting effect.

[0067] Injecting reinforcement slurry between the gap between the reinforcement pile structure 1 and the soil layer of the soft soil roadbed section 3, including: performing a first grouting treatment between the gap between the reinforcement pile structure 1 and the soil layer of the soft soil roadbed section 3, injecting a casing material to seal the annular space between the reinforcement pile structure 1 and the holes in the soil layer of the soft soil roadbed section 3, forming a cement stone body, and preventing the slurry from flowing everywhere and affecting the entire grouting effect;

[0068] The cement-stone body of the first grouting is split, and the second grouting treatment is carried out in the gap of the cement-stone body, so that the injected cement slurry spreads around the hole and reinforces the soil around the hole. In the casing material injected during the first grouting treatment, the ratio of cement to water is 1:0.4-0.5, and in the cement-water mixture, an early strength high-efficiency water reducer is added at a ratio of 1%-2% of the mixture.

[0069] The first grouting treatment is carried out between the reinforcement pile structure 1 and the soil layer of the soft soil roadbed section 3, and the casing material is injected to close the annular space between the reinforcement pile structure 1 and the holes of the soil layer of the soft soil roadbed section 3 to form a cement stone body, including:

[0070] First, transfer cement from the storage area to the slurry preparation area, and ensure that there is enough water in the reservoir to prepare the casing material slurry according to the preset mix ratio;

[0071] The casing material slurry is injected into the gap between the reinforcement pile structure 1 and the soil layer of the soft soil roadbed section 3 at a grouting pressure of 0.3-0.4 MPa to close the annular space between the reinforcement pile structure 1 and the holes in the soil layer of the soft soil roadbed section 3;

[0072] The bottom grouting method is adopted when grouting the casing material. The grouting pipe adopts a 22mm diameter PVC pipe. The grouting pipe is fixed together with the reinforcement pile structure 1, and grouting is carried out after it is lowered to 30cm from the bottom of the hole. The bottom of the reinforcement pile structure 1 is connected to the bottom of the hole through a triangular bottom bracket 7. A centering frame 8 is provided between the reinforcement pile structure 1 and the side wall of the hole. The casing material slurry flushes the valve sleeve at the end of the grouting pipe, and grouting is performed until grouting emerges from the hole mouth to fill the gap between the reinforcement pile structure 1 and the hole. During the grouting process, there is no casing material slurry in the reinforcement pile structure 1. After the casing material slurry reaches the top of the reinforcement pile structure 1, the first grouting is terminated, and the casing material slurry forms a cement stone body after drying and hardening.

[0073] The cement-stone body of the first grouting is split, and the second grouting treatment is carried out in the gap of the cement-stone body, so that the injected cement slurry spreads around the hole and reinforces the soil around the hole, including:

[0074] After the casing material slurry dries and hardens to form a cement stone body, secondary splitting grouting is carried out. Except for the top 1.5m range of the cement stone body, splitting grouting is carried out in the rest of the range.

[0075] The secondary split grouting adopts segmented multiple split grouting, and the grouting is carried out in sections from bottom to top. The segment length of each grouting area is not more than 0.5m. Grouting is carried out using a grouting gun with grout stoppers on both the upper and lower sides;

[0076] During the secondary splitting grouting, after splitting the cement stone body of the primary grouting, the reinforced pile structure 1 is used as the grouting pipe for the secondary splitting grouting, and the cement slurry is controlled to be continuously injected at a pressure of 1.5Mpa for 5 minutes, or when the amount of cement slurry for the secondary grouting reaches 150L / m, the second grouting is terminated.

[0077] 4-6 hours after the first grouting is completed, the casing material slurry dries and hardens to form a cement stone body, and the second splitting grouting is carried out. During the splitting grouting, except for the 1.5m range at the top of the cement stone body, the rest of the range is split grouting;

[0078] 4-6 hours after the completion of the first grouting, the casing material slurry has usually dried and hardened to form a cement stone body. At this time, the secondary splitting grouting is carried out. During the splitting grouting, the slurry is injected into the cement stone body by a high-pressure grouting pump. Since the pressure of the slurry is greater than the tensile strength of the soil or rock, the slurry will produce cracks in the stone body. When the pressure of the slurry reaches a certain level, the cement stone body will be subjected to tensile stress, thereby producing cracks in the weak parts of the stone body, such as weak interlayers, joints, and fissures. Cracks usually occur in the parts of the stone body that need reinforcement the most, that is, where stress is concentrated or the bearing capacity is insufficient. As cracks form, slurry will enter these cracks under pressure, fill the cracks and harden to form new stone bodies, thereby reinforcing the soil layer or rock; the secondary grouting adopts segmented multiple splitting grouting, with a segment length of no more than 0.5m, and the grouting is carried out in segments from bottom to top, which can ensure that each segment can effectively form cracks and fill with slurry, gradually reinforcing the entire stone body. Grouting can be carried out with a grouting gun with grouting plugs on both the upper and lower sides. During the secondary splitting grouting, the slurry ratio is cement: water = 1:0.8, During grouting, the reinforced pile structure 1 can be used as a grouting pipe for secondary splitting grouting. The reinforced pile structure 1 in the present invention is preferably a steel flower pipe. By splitting the cement stone body of the primary grouting, the slurry spreads to the surroundings to reinforce the soil body; when the secondary grouting splitting grouting pressure reaches 1.5Mpa, the embankment soil range can be reduced to 1Mpa and maintained for 5 minutes without grouting, or the secondary grouting cement slurry dosage reaches 150L / m (the grouting volume in the soft soil layer is controlled at 50L / m), and the grouting volume of the remaining soil layers is controlled at 150L / m. In order to avoid affecting the surrounding roads during the construction process, the grouting pressure must be strictly controlled during the grouting process. As the slurry is continuously injected, the pressure of the slurry gradually increases. In order to prevent the slurry pressure from exceeding the bearing capacity of the stratum, the grouting process needs to be monitored during grouting. If obvious uplift and deformation are found on the surface, the grouting should be stopped immediately and the causes of the deformation and uplift should be found. Depending on the causes, the grouting pressure and slurry volume should be readjusted to reduce the impact on surrounding roads.

[0079] After the second grouting, compressed air can be injected through the reinforcement pile structure 1, so that the slurry injected for the second time can fit tightly with the cracks, ensuring the grouting density while penetrating into the soil layer, so that the nearby soil layer is solidified and the reinforcement effect is improved. After the compressed air is injected, before the slurry injected for the second time hardens, the third slurry injection work is carried out to further compact the slurry and form a stable anti-subsidence structure.

[0080] After the second grouting, by injecting compressed air into the reinforced pile structure 1, the following significant effects can be achieved: 1. Improving the fit between the slurry and the cracks. The pressure of the compressed air can help the slurry fill the cracks better, making it fit tightly with the crack wall, ensuring that the slurry is evenly distributed in the cracks and reducing the gaps. After the slurry fits tightly with the crack wall, it can enhance the bonding force between the slurry and the surrounding soil or rock, and improve the stability of the overall structure. 2. Promoting slurry penetration. The pressure of the compressed air can push the slurry to penetrate into the tiny pores and cracks inside the soil layer, further reinforcing the soil layer. This penetration can significantly improve the density and integrity of the soil layer. Through the action of compressed air, the slurry can be evenly distributed in the soil layer, avoiding excessive or insufficient local slurry, and ensuring the uniformity of the reinforcement effect. 3. Accelerating the solidification of the soil layer and promoting the solidification reaction. The pressure of the compressed air can accelerate the chemical reaction in the slurry and promote the solidification process of the slurry. This is very beneficial for improving the reinforcement effect and shortening the construction period. Through the action of compressed air, after the slurry solidifies in the soil layer, it can significantly improve the strength and stability of the soil layer and reduce settlement and deformation.

[0081] After the grouting is completed, the redundant reinforcement pile structure 1 on the top is cut off, the reinforced concrete integral slab 2 is constructed, and then the road surface structure is re-paved.

[0082] In the present invention, the construction process of arranging the reinforced concrete integral slab 2 on the top of the multi-row reinforcement pile structure 1 includes:

[0083] Milling the soft soil roadbed section 3 where multiple rows of reinforcement pile structures 1 are buried, and cleaning up the waste residue;

[0084] Then the redundant parts above the multiple rows of reinforcement pile structures 1 are cut and connected with steel bars;

[0085] After welding and connecting the top of the multi-row reinforcement pile structure 1 with the steel bars, pour concrete slurry to form a reinforced concrete integral slab 2. When pouring concrete, a vibrating rod must be used to vibrate and compact it to ensure that it is compacted. At the same time, the vibrating rod should be at least 2 cm away from the steel mesh and should be vibrated carefully to ensure quality;

[0086] After the concrete is poured, spray the curing agent first, then cover it with a moisturizing film, geofelt, geotextile, sacks, straw bags, straw mats, etc., and finally sprinkle water to maintain moisture and curing. Curing must be timely. After the concrete strength reaches more than 80%, construction of the asphalt pavement can be carried out.

[0087] Embodiment 2

[0088] See also Figure 1-11In an anti-settlement construction method for soft soil roadbed of expressway provided by the present invention, a reinforcement pile structure 1 comprises: a steel flower pipe for inserting into a hole, the steel flower pipe comprises: a plurality of pipe bodies 4, two adjacent pipe bodies 4 are connected by a steel pipe joint 5, a bottom sealing steel plate 6 is welded at the bottom of the pipe body 4, a triangular bottom bracket 7 for supporting at the bottom of the hole is welded at the bottom of the bottom sealing steel plate 6, so that it has a certain distance from the bottom of the hole, a centering frame 8 for supporting at the side wall of the hole is provided on the side of the pipe body 4 to ensure that it is installed in the center of the hole and improve the installation accuracy, a slurry outlet hole for secondary grouting is provided on the side of the pipe body 4, a slurry stop plug is provided in the slurry outlet hole, when the pressure in the pipe body 4 reaches a preset value, the slurry stop plug can be ruptured, so that the slurry or compressed air in the pipe body 4 is output through the slurry outlet hole.

[0089] The centering frame 8 includes: a plurality of steel bars welded to the side of the pipe body 4, the outer wall of the steel bars is in contact with the side wall of the hole, which can not only play a centering effect, but also improve the stability of the connection between the slurry and the pipe body 4 after the slurry is injected, improve the supporting effect of the pipe body 4, and reduce the probability of the pipe body 4 producing longitudinal displacement.

[0090] Four transverse perforations are evenly arranged around the side wall of each tube body 4, and puncturable elastic sealing pads 9 are arranged in the four transverse perforations. The four transverse perforations are connected and communicated with four guide transverse tubes 10 fixedly arranged on the inner wall of the tube body 4. A reinforcing tube 11 is sealed and slidably connected in each guide transverse tube 10. A conical piercing head 12 is arranged at one end of the reinforcing tube 11 close to the elastic sealing pad 9, and a flaring and gathering nozzle 13 is arranged at one end of the reinforcing tube 11 away from the elastic sealing pad 9. The diameter of the flaring and gathering nozzle 13 away from the end of the reinforcing tube 11 is larger than that of the flaring and gathering nozzle. The diameter of the connection end of the nozzle 13 and the enhanced penetration tube 11; the middle part of the enhanced penetration tube 11 is connected to the slider 14 slidably arranged in the limiting groove of the side wall of the guide cross tube 10, the slider 14 is rotatably connected to the lower end of the push connecting rod 15, the upper end of the push connecting rod 15 is rotatably connected to the pressing seat 16, the middle part of the pressing seat 16 is slidably arranged on the support frame 17 of the inner wall of the tube body 4, the top of the pressing seat 16 is threadedly connected to the external threaded tube 18, the external threaded tube 18 is rotated on two tube frames 19 on the inner wall of the tube body 4, and the inner side of the external threaded tube 18 is provided with a multi-faceted hole for inserting a multi-faceted rod. A plurality of expansion holes 20 are evenly arranged around the side wall of the enhanced penetration tube 11, and an expansion air bag 21 is glued in each of the plurality of expansion holes 20.

[0091] The working principle and technical effects of the above technical solution are as follows:

[0092] The four transverse perforations on the side wall of the tube body 4 are all provided with puncturable elastic plugging pads 9, which can prevent the slurry from entering the tube body 4 through the transverse perforations during the first grouting. After the first grouting is completed, before the casing material slurry is dried and hardened, the cement stone body is not formed. At this time, the external threaded tubes 18 in the multiple tube bodies 4 are penetrated through the multi-faceted holes by the multi-faceted rods. The multi-faceted rods are rotated to control the synchronous rotation of the multiple external threaded tubes 18. When the external threaded tubes 18 rotate, their contact position with the pressing seat 16 can be changed. In the initial state, the pressing seat 16 is at the highest horizontal position, and the multi-faceted rods are rotated to control the contact position of the external threaded tubes 18 with the pressing seat 16. The external threaded tube 18 drives the pressing seat 16 to move downward in the tube body 4, and the downward movement of the pressing seat 16 drives one end of the multiple pushing connecting rods 15 to move downward, and the other ends of the multiple pushing connecting rods 15 drive the multiple sliding blocks 14 to move in the direction away from the center of the tube body 4 in the limiting grooves on the side walls of the multiple guiding transverse tubes 10, thereby controlling the multiple reinforced penetration tubes 11 to move in the direction of the multiple elastic plugging pads 9 in the multiple guiding transverse tubes 10. After the conical piercing heads 12 of the multiple reinforced penetration tubes 11 pierce the multiple elastic plugging pads 9, they pass through the gap between the tube body 4 and the soil layer of the soft soil roadbed section 3 and the casing slurry. Liquid can be inserted into the soil layer through the conical piercing head 12, which can not only limit the longitudinal position and reduce the probability of the pipe body 4 being displaced in the up and down directions, but also the enhanced penetration pipe 11 can be stably connected with the cement stone body formed between the pipe body 4 and the soil layer of the soft soil roadbed section 3, and reduce the probability of the pipe body 4 being deviated during the secondary splitting grouting. In addition, when grouting is performed through the pipe body 4 to the gap between the pipe body 4 and the soil layer of the soft soil roadbed section 3, part of the slurry can also enter the enhanced penetration pipe 11 through the expanded converging nozzle 13, and generate pressure on the expansion airbags 21 at the multiple expansion holes 20 of the enhanced penetration pipe 11, After the part of the pipe body with the expansion bag 21 of the reinforced penetration pipe 11 is inserted into the soil layer, as the expansion bag 21 expands, it can be tightened in the soil layer, which can not only squeeze the soil layer near the pipe body 4 to enhance stability, but also as the slurry in the expansion bag 21 solidifies, a more stable connection is formed between the part of the pipe body with the expansion bag 21 and the soil layer, the relative stability of the pipe body 4 and the soil layer is higher, and multiple expansion bags 21 are used to contact the soil layer, so that they can expand to different extents according to the soil conditions at different positions, and adaptively adjust to meet the needs of different situations.

[0093] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0094] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0095] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A method for preventing subsidence of soft soil roadbed of expressway, characterized in that: The method comprises the following steps: A plurality of rows of reinforcement pile structures (1) are buried in the road extension direction of the soft soil roadbed section (3); Injecting reinforcement slurry between the gap between the reinforcement pile structure (1) and the soil layer of the soft soil roadbed section (3); A reinforced concrete integral plate (2) is arranged on the top of the multiple rows of reinforced pile structures (1), and the reinforced concrete integral plate (2) is connected to the multiple rows of reinforced pile structures (1).

2. The anti-settling construction method for soft soil roadbed of expressway according to claim 1, characterized in that: The reinforcement pile structure (1) is buried in a plurality of rows along the road extension direction of the soft soil roadbed section (3), comprising: The soft soil roadbed section (3) is measured and laid out and drilled to obtain holes, and a reinforcement pile structure (1) is inserted into the holes.

3. The anti-settling construction method for soft soil roadbed of expressway according to claim 2, characterized in that: The reinforcement pile structure (1) comprises: a steel flower tube for inserting into a hole.

4. The anti-settlement construction method for soft soil roadbed of expressway according to claim 3, characterized in that: The soft soil roadbed section (3) is measured and laid out and drilled to obtain holes, and a reinforcement pile structure (1) is inserted into the holes, including: According to the requirements of the steel pipe grouting construction process, draw the grouting pile position map, and use the total station to measure the hole position and ground elevation, as well as the hole size and position, and mark them; According to the drilling requirements, select a suitable drilling machine, put the drilling machine in place according to the marked position of the hole, and perform drilling to obtain the hole; Insert the steel flower tube to the bottom of the hole and make it vertical in the middle of the hole; Place the upper cover of the steel flower pipe on the top of the steel flower pipe.

5. The anti-settling construction method for soft soil roadbed of expressway according to claim 4, characterized in that: The steel flower pipe is made of hot-rolled seamless steel pipe. The joints of the steel flower pipe are extended by steel sleeves. A sealing steel plate with a diameter equal to the outer diameter of the steel flower pipe is welded to the bottom of the steel flower pipe.

6. The anti-settlement construction method for soft soil roadbed of expressway according to claim 5, characterized in that: The diameter of the steel flower tube is 89mm, the wall thickness of the steel flower tube is 4.5mm; the diameter of the hole is 180mm.

7. The anti-settlement construction method for soft soil roadbed of expressway according to claim 1, characterized in that: Injecting reinforcement slurry between the gap between the reinforcement pile structure (1) and the soil layer of the soft soil roadbed section (3) includes: Performing a first grouting treatment between the reinforcement pile structure (1) and the soil layer of the soft soil roadbed section (3), injecting casing material to seal the annular space between the reinforcement pile structure (1) and the holes in the soil layer of the soft soil roadbed section (3), thereby forming a cement stone body; The cement-stone body injected for the first time is split, and a second grouting treatment is carried out in the gaps of the cement-stone body, so that the injected cement slurry diffuses around the hole and reinforces the soil around the hole.

8. The anti-settling construction method for soft soil roadbed of expressway according to claim 7, characterized in that: In the casing material injected during the first grouting treatment, the ratio of cement to water is 1:0.4-0.5, and in the mixture of cement and water, an early strength high-efficiency water reducing agent is added at a ratio of 1%-2% of the mixture.

9. The anti-settlement construction method for soft soil roadbed of expressway according to claim 7, characterized in that: The first grouting treatment is performed between the reinforcement pile structure (1) and the soil layer of the soft soil roadbed section (3), and the casing material is injected to seal the annular space between the reinforcement pile structure (1) and the holes in the soil layer of the soft soil roadbed section (3), thereby forming a cement stone body, including: First, the cement is transferred from the storage area to the slurry making area, and the cement and the water in the reservoir are used to make the casing material slurry according to the preset mix ratio; The casing material slurry is injected into the gap between the reinforcement pile structure (1) and the soil layer of the soft soil roadbed section (3) at a grouting pressure of 0.3-0.4 MPa to close the annular space between the reinforcement pile structure (1) and the holes in the soil layer of the soft soil roadbed section (3); The casing material is grouted by the bottom grouting method. The grouting pipe is a 22 mm diameter PVC pipe. The grouting pipe is fixed together with the reinforced pile structure (1) and lowered to 30 cm from the bottom of the hole for grouting. The casing material slurry flushes the valve sleeve at the end of the grouting pipe. Grouting is performed until grout emerges from the hole mouth to fill the gap between the reinforced pile structure (1) and the hole. During the grouting process, the reinforced pile structure (1) is kept free of casing material slurry. When the casing material slurry reaches the top of the reinforced pile structure (1), the first grouting is terminated. The casing material slurry is dried and hardened to form a cement stone body.

10. The anti-settlement construction method for soft soil roadbed of expressway according to claim 9, characterized in that: The cement-stone body of the first grouting is split, and the second grouting treatment is carried out in the gap of the cement-stone body, so that the injected cement slurry spreads around the hole and reinforces the soil around the hole, including: After the casing material slurry dries and hardens to form a cement stone body, secondary splitting grouting is carried out. Except for the top 1.5m range of the cement stone body, splitting grouting is carried out in the rest of the range. The secondary splitting grouting adopts segmented multiple splitting grouting. The grouting is carried out in segments from bottom to top. The segment length of each grouting area is not more than 0.5m. During grouting, the cement slurry is controlled to be injected continuously at a pressure of 1.5Mpa for 5min. When the amount of cement slurry for the secondary grouting reaches 150L / m, the second grouting is terminated.

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