Undisturbed soil foundation construction method and device based on advanced pre-grouting reinforcement

Abstract

The invention relates to the technical field of power transmission line foundations, and discloses an undisturbed soil foundation construction method based on advanced pre-grouting reinforcement, which comprises the following steps: drilling an original ground soil foundation, and filling gaps of the drilled soil foundation for pre-reinforcement; and the peripheral soil matrix of the to-be-drilled space is pre-reinforced to form a stable stone body, and foundation pit excavation is conducted on the pre-reinforced soil body. The device based on the construction method comprises drilling and grouting equipment; the drilling grouting equipment comprises a grouting drill bit, a push rod section, a gear, driving equipment, a grouting pump, a grouting pipe and a slurry tank. According to the method, the strength and stability of the natural soil body are remarkably improved through pre-reinforcement, a solid foundation is provided for follow-up construction, and the safety risk in the construction process is reduced; it is ensured that the soil foundation reaches a stable state before excavation, soil collapse and deformation in the excavation process are avoided, and the construction efficiency and quality are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power transmission line foundations, and in particular to a construction method and device for an undisturbed soil foundation based on advanced pre-grouting reinforcement. Background Art

[0002] In recent years, with the increasing development and utilization of clean energy such as photovoltaics and wind power in the northwest region, transmission lines have inevitably entered deserts, Gobi, and wastelands. The complex geological environment has brought huge challenges to the construction of transmission lines.

[0003] In deserts or desert edges, Gobi and some loess areas, due to the high sand content in the soil, collapse accidents are very likely to occur when the transmission line foundation adopts the original soil foundation (dig foundation, excavation foundation, etc.), causing the project plan to be repeated or changed, and greatly increasing the project construction period and investment.

[0004] Due to the loose structure, low strength, and poor stability of sandy soil, saturated silt and fine sand become tightly packed together during construction disturbance, preventing the timely drainage of pore water within the sand. This causes a sudden increase in pore water pressure, reducing the contact force between sand particles and frictional resistance. This can easily lead to localized liquefaction, loss of strength, and significant foundation pit collapse. To address this situation, the transmission line industry often uses excavated foundations in sandy soils. However, excavated foundations significantly damage the landscape and vegetation, hindering environmental protection. While undisturbed soil foundations (such as bored and hollowed foundations) offer a smaller construction surface, less damage to the landscape, and maximize the bearing capacity of the undisturbed soil, they are highly susceptible to pore collapse when applied to sandy soils. Therefore, a construction method suitable for undisturbed soil foundations in sandy soils is urgently needed. Summary of the Invention

[0005] In order to solve the existing problems, the present invention provides an original soil foundation construction method and device based on advance pre-grouting reinforcement, aiming to make full use of the bearing capacity advantages of the original soil, while avoiding the damage to the original landform and vegetation caused by large-scale foundation excavation, reducing construction risks, saving production costs, and reducing the construction earthwork volume, so as to achieve resource conservation, environmental friendliness, and obvious economic benefits.

[0006] In order to achieve the above objectives, the present invention provides the following technical solutions.

[0007] In the first aspect, the present invention provides a method for constructing an original soil foundation based on advance pre-grouting reinforcement, comprising the following steps: drilling the original ground soil foundation, and pre-reinforcing the soil foundation gaps in the drilled space; pre-reinforcing the soil foundation around the space to be drilled to form a stable stone body, and excavating a foundation pit for the pre-reinforced soil body.

[0008] As a further improvement of the present invention, the pre-reinforcement takes the form of ground static pressure grouting to perform pre-grouting on the original ground soil foundation before excavation.

[0009] As a further improvement of the present invention, the ground static pressure grouting form is selected from one or more of filling grouting, penetration grouting, compaction grouting, and splitting grouting.

[0010] As a further improvement of the present invention, the grouting material for pre-grouting is selected from inorganic grouting material or organic grouting material.

[0011] As a further improvement of the present invention, the inorganic grouting material is one or more of cement-calcium chloride solution, cement-triethanolamine-calcium chloride solution, ultrafine cement, wet-ground ultrafine cement, paste cement, cement-water glass double slurry, clay-bentonite slurry, water glass-calcium chloride slurry, and water glass-sodium aluminate slurry; the organic grouting material is one or more of pulp waste liquid-sodium dichromate slurry, pulp waste liquid-ammonium persulfate slurry, urea-formaldehyde resin-sulfuric acid slurry, urea-formaldehyde-ferric oxide slurry, water-soluble polyurethane slurry, and water-insoluble polyurethane slurry.

[0012] In the second aspect, the present invention also discloses a device for the construction method of an original soil foundation based on advance pre-grouting reinforcement, including drilling and grouting equipment; the drilling and grouting equipment includes a grouting drill bit, a push rod segment, gears, a driving device, a grouting pump, a grouting pipe and a slurry tank; an annular cutter head is provided on one side of the grouting drill bit, and a slot matching the push rod segment is provided on the other side of the grouting drill bit; a grouting hole is provided on the grouting drill bit; slots are respectively provided on both sides of the push rod segment, the slot on one side corresponds to the slot of the grouting drill bit, and the slot on the other side corresponds to the slot of the next push rod segment; the push rod segment farthest from the grouting drill bit is provided with an external thread, and the push rod segment is driven by the gear screw; the driving device rotates the gear; the grouting drill bit and the push rod segment are both provided with a hollow inner cavity, the hollow inner cavities of the grouting drill bit and the push rod segment are connected to each other, and are connected to the grouting pump and the slurry tank in sequence through the grouting pipe.

[0013] As a further improvement of the present invention, it also includes excavation equipment; the excavation equipment is a rotary drilling rig or a mechanical Luoyang shovel.

[0014] As a further improvement of the present invention, there are a plurality of push rod segments; the plurality of push rod segments are connected by corresponding slots to form a push rod as a whole that can be assembled and disassembled along the length direction.

[0015] As a further improvement of the present invention, the spacing between the grouting holes is 1.5 times the preset grouting penetration range.

[0016] As a further improvement of the present invention, the grouting pipe also includes a front section of the grouting pipe, and the front section of the grouting pipe is made of a seamless steel pipe with a diameter of 50 mm or 70 mm.

[0017] The present invention has the following beneficial effects: Through pre-reinforcement, the strength and stability of the soil can be significantly improved, providing a solid foundation for subsequent construction and reducing safety risks during the construction process; ensuring that the soil foundation has reached a stable state before excavation, avoiding soil collapse and deformation during excavation, and improving construction efficiency and quality.

[0018] Preferably, ground static pressure grouting can ensure uniform distribution of grouting materials, effectively fill the voids in the soil, and improve the integrity and strength of the soil; static pressure grouting is a method of injecting slurry into foundation soil through static pressure, and is suitable for foundation reinforcement of sandy soil, clay soil, etc.

[0019] Preferably, according to the characteristics of different soils and construction requirements, appropriate grouting forms are selected, such as filling grouting, penetration grouting, compaction grouting, and splitting grouting, which can more flexibly cope with various complex geological conditions, more effectively reinforce the soil, and improve the quality of the project.

[0020] Alternatively, inorganic grouting materials have advantages such as high strength and good durability, while organic grouting materials have advantages such as strong plasticity and good grouting effect. Selecting the appropriate grouting material according to actual needs can ensure the best grouting effect under cost considerations.

[0021] The construction device disclosed in the present invention can realize precise grouting of soil, ensure uniform distribution of grouting materials, and improve grouting efficiency and quality; the annular cutter head can cut the soil and provide immediate support after drilling, reduce the natural filling of sand and soil after drilling, and provide stable structural support for the penetration of grouting materials; the grouting holes are used to inject grouting materials into the soil to achieve grouting reinforcement; the design of the slot and external thread facilitates the connection and disassembly of the push rod section, and the length of the push rod section can be adjusted according to actual needs, thereby improving the flexibility and applicability of the equipment; the design of the hollow inner cavity can ensure that the grouting material passes smoothly through the grouting drill bit and the push rod section, thereby improving grouting efficiency.

[0022] Preferably, the excavation equipment is simple to operate, can achieve rapid and efficient excavation of the soil, and improve construction efficiency and quality.

[0023] Optionally, the push rod section is made of a lightweight steel pipe, which is easy to carry and install, and the clip-on design allows the push rod as a whole to be adjusted in length according to the drilling depth, thereby improving the flexibility and applicability of the equipment.

[0024] Preferably, it is ensured that the grouting material can fully penetrate and fill the voids in the soil to improve the grouting effect.

[0025] Optionally, the seamless steel pipe has the advantages of high strength and good corrosion resistance. As the front section of the grouting pipe entering the soil, it can ensure the grouting pressure during the grouting process and improve the stability and durability of the grouting pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are merely schematic and are used to facilitate understanding of the present invention. They are not intended to limit the shapes and proportional dimensions of the components of the present invention. In the drawings: Figure 1 This is a flow chart of an undisturbed soil foundation construction method based on advance pre-grouting reinforcement as described in Example 1; Figure 2 This is a schematic diagram of a plan view of a space drilled out of an undisturbed soil foundation construction method based on advance pre-grouting reinforcement as described in Example 1; Figure 3 Schematic diagram of an apparatus for an undisturbed soil foundation construction method based on advance pre-grouting reinforcement as described in Example 1; Among them, 1. Grouting drill bit; 2. Push rod section; 3. Gear; 4. Driving equipment; 5. Grouting pump; 6. Grouting pipe; 7. Slurry tank; 8. Grouting hole; 9. Slot; 10. External thread; 11. Grouting mobile platform; 12. Front section of grouting pipe. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0028] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be an element centered thereon. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an element centered thereon. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] The present invention proposes an undisturbed soil foundation construction method based on advanced pre-reinforcement, which solves the problem of using undisturbed soil foundation construction in deserts, Gobi, soil layers with high sand content, etc., can give full play to the advantages of high bearing capacity of undisturbed soil foundation, and use soil instead of formwork to reduce damage to the original landform and vegetation. It can make full use of mechanized equipment for foundation pit excavation, reduce construction risks, and save project investment.

[0031] Example 1 like Figure 1 As shown, a construction method of an original soil foundation based on advance pre-grouting reinforcement includes the following steps: drilling the original ground soil foundation, and pre-reinforcing the soil foundation gaps in the drilled space; pre-reinforcing the soil foundation around the drilled space to form a stable stone body, and excavating the foundation pit for the pre-reinforced soil body.

[0032] The pre-grouting is carried out by static pressure grouting on the original ground soil before excavation. Static pressure grouting is a method of injecting slurry into the foundation soil under static pressure, and is suitable for strengthening foundations such as sandy soil and clay soil.

[0033] The ground static pressure grouting form is selected from one or more of filling grouting, penetration grouting, compaction grouting and splitting grouting.

[0034] The grouting material for the pre-grouting is selected from inorganic grouting materials or organic grouting materials. The inorganic grouting material is one or more of cement-calcium chloride solution, cement-triethanolamine-calcium chloride solution, ultrafine cement, wet-ground ultrafine cement, paste cement, cement-water glass double slurry, clay-bentonite slurry, water glass-calcium chloride slurry, and water glass-sodium aluminate slurry; the organic grouting material is one or more of pulp waste liquid-sodium dichromate slurry, pulp waste liquid-ammonium persulfate slurry, urea-formaldehyde resin-sulfuric acid slurry, urea-formaldehyde-ferric oxide slurry, water-soluble polyurethane slurry, and non-water-soluble polyurethane slurry. Inorganic grouting materials have the advantages of high strength and good durability, while organic grouting materials have the advantages of strong plasticity and good grouting effect. Selecting the appropriate grouting material according to actual needs can ensure that the grouting effect is optimal under cost considerations.

[0035] like Figure 2 As shown, the pre-grouting is evenly implemented around the original soil foundation, and the pre-grouting points form a plum blossom shape on the plane.

[0036] Specifically, the present invention provides a method for constructing an undisturbed soil foundation based on advanced pre-grouting reinforcement, comprising the following steps: Before construction, a comprehensive geological survey is conducted to understand the foundation's soil structure, groundwater level, soil type, and other information to determine an appropriate grouting plan. Based on the geological survey results, a specific grouting plan is designed, including the selection of grouting materials, setting the grouting pressure, and arranging the grouting holes 8. Considering the dry climate and loess characteristics of the Northwest region, grouting materials with good water retention and shrinkage resistance can be selected, such as cement slurry with fiber reinforcement, modified cement slurry, or water-soluble polyurethane slurry. Environmentally friendly grouting materials are preferred to minimize the impact on the local ecological environment. Modified cement slurry has excellent water retention and shrinkage resistance, making it suitable for dry environments. Water-soluble polyurethane slurry has excellent fluidity and permeability, allowing it to penetrate into small cracks in the soil, creating an effective reinforcement effect. The grouting pressure should be controlled between 0.2 and 0.6 MPa. Grouting can be performed using either a backward or staged forward grouting drill bit 1. The grouting pressure can be appropriately increased to between 1 and 3 MPa in the later stages of grouting.

[0037] The working face is closed and a mobile grouting platform 11 (including a slurry tank 7, a grouting pump 5 and a grouting pipe 6) is arranged. The mobile grouting platform 11 should be placed behind and to the side of the working face to reduce the interference between drilling and grouting on the working face and improve work efficiency. According to the designed grouting volume, the slurry material should be piled at a position close to the working face but without affecting the construction of the working face.

[0038] Use drilling and grouting equipment to drill holes at the predetermined locations. The drilling depth should meet the design requirements, typically exceeding the foundation's bottom surface by a certain depth to ensure effective grouting. After drilling is completed, a grouting pipe 6 is installed within the inner cavity of the grouting drill bit 1 and the push rod section 2. The grouting pipe 6 should extend to the grouting drill bit 1 to ensure that the grouting liquid is evenly distributed throughout the drilled soil cavity. During the grouting process, the grouting pressure must be strictly controlled to avoid soil cracking or grouting liquid loss due to excessive pressure. In dry, loose loess and sandy soils, the grouting pressure should be appropriately reduced to avoid soil fragmentation or grouting liquid loss due to excessive pressure. In very loose soil layers, the initial pressure can be lower to prevent soil fragmentation. Furthermore, the grouting speed should be controlled to avoid excessive speed, which may prevent the grouting liquid from fully penetrating and solidifying. The grouting speed should be kept between 10 and 30 cubic meters per hour. For sandy soils with higher permeability, the speed can be increased, while for loess, it should be slowed down to ensure that the grouting liquid fully penetrates and solidifies. The density and depth of the grouting holes 8 on the grouting drill bit 1 should be appropriately arranged based on the looseness and moisture content of the soil to ensure even distribution of the grouting liquid throughout the entire reinforcement area. The number of grouting holes 8 should be determined based on the diameter of the original soil foundation and the spacing between the grouting holes 8. The distance between the grouting holes 8 and the edge of the original soil foundation should be 0.5 times the grouting penetration range. The burial depth of the grouting holes 8 should be greater than the original soil foundation depth. During the grouting process, real-time monitoring should be performed using technologies such as geological radar and seismic wave analysis to allow timely adjustment of grouting parameters to ensure effective reinforcement. Considering the potential impacts of the rainy season in Northwest China, such as flash floods and hailstorms in high-altitude mountainous areas, grouting should be performed during the dry season to minimize the impact of moisture on the grouting effect. Grouting termination criteria can be based on grouting time or grouting volume. Grouting can be terminated when the grouting time reaches the slurry's setting time but the grouting volume has not yet reached the desired setting time. Grouting can also be terminated when the grouting volume reaches the designed value but the slurry has not yet reached the desired setting time or when there is no significant fluctuation in the grouting pressure. Keep good grouting records during the grouting process, i.e. the grouting time, grouting pressure, grouting volume, etc. of each hole.

[0039] After grouting is completed, a certain amount of time is required to allow the grouting liquid to fully solidify in the soil and form a stable stone mass. The length of this period depends on the setting time of the grouting material used. After the stone mass is formed, strength testing is performed to ensure that it meets the design requirements. After grouting is completed, it is recommended to allow at least 24 to 48 hours for the grouting liquid to solidify. If the grouting liquid solidifies quickly, the next grouting phase can be started 4 to 12 hours later. The specific time should be adjusted according to the type of grouting material and the ambient temperature. In cold weather, a longer setting time may be required. Strength testing can be performed by core sampling: After the setting time is complete, a core drill is used to randomly sample the grouting soil within the reinforced area. Alternatively, a visual inspection and pressure test can be performed, relying on experience to determine the appropriate strength for excavation. The ground surface should be observed for any obvious deformation features. If necessary, ground uniformity can be monitored using standard penetration, light dynamic penetration, static penetration, or surface wave methods.

[0040] Finally, waste generated during construction, especially the packaging and residues of grouting materials, will be properly disposed of to avoid contamination of soil and water sources. After construction is completed, the construction area will be restored to its original ecological state by planting plants suitable for the local climate.

[0041] like Figure 3 As shown, the present invention also discloses a device for an original soil foundation construction method based on advance pre-grouting reinforcement, including a drilling grouting device; the drilling grouting device includes a grouting drill bit 1, a push rod segment 2, a gear 3, a drive device 4, a grouting pump 5, a grouting pipe 6 and a slurry tank 7. The construction device disclosed in the present invention can achieve precise grouting of the soil, ensure uniform distribution of grouting materials, and improve grouting efficiency and quality; the annular cutter head can cut the soil and provide immediate support after drilling, reduce the natural bridging of sand and soil after drilling, and provide stable structural support for the penetration of grouting materials; the grouting hole 8 is used to inject grouting materials into the soil to achieve grouting reinforcement; the design of the slot 9 and the external thread 10 facilitates the connection and disassembly of the push rod segment 2, and the length of the push rod segment 2 can be adjusted according to actual needs, thereby improving the flexibility and applicability of the equipment; the design of the hollow inner cavity can ensure that the grouting material passes smoothly through the grouting drill bit 1 and the push rod segment 2, thereby improving grouting efficiency. The grouting pump 5, the grouting pipe 6 and the slurry tank 7 can be installed on a grouting mobile platform 11, and the grouting mobile platform 11 can be carried by a pump truck and a trailer.

[0042] Specifically, an annular cutter head is provided on one side of the grouting drill bit 1. The annular cutter head can be composed of a cutter head body, a cutting edge, and a chip groove. The diameter of the annular cutter head can be 80 mm to 120 mm. The cutting edge is located at the front end of the cutter head body and is responsible for cutting soil or rock. The chip grooves are distributed on the side of the cutter head body to guide the cut soil or rock chips out. The cutter head shape can be conical, cylindrical, flat, or a special shape, such as with spiral blades. The cutter head material generally includes steel, cemented carbide, and diamond. For gravel soil, steel can be selected. A slot 9 is provided on the other side of the grouting drill bit 1 to match the push rod segment 2. The slot 9 can be semicircular, square, elliptical, or polygonal. The grouting drill bit 1 is provided with a grouting hole 8. The push rod segment 2 is provided with a slot 9 on both sides, with the slot 9 on one side corresponding to the slot 9 of the grouting drill bit 1 and the slot 9 on the other side corresponding to the slot 9 of the next push rod segment 2. The push rod section 2 can be made of a lightweight hollow steel pipe.

[0043] An external thread 10 is provided on the push rod section 2 farthest from the grouting drill bit 1, and the push rod section 2 and the gear 3 are screw-driven; a dust-proof hose or a flexible cover can be provided on the outside of the screw transmission part to avoid dust pollution; the pitch of the external thread 10 can be 1 / 4 to 1 / 2 of the number of teeth of the gear 3, and the number of teeth can be selected between 20 and 60; the drive device 4 rotates the gear 3, and the drive device 4 can select a diesel engine, a gasoline engine or an electric motor; the output power of the drive device 4 can be between 20kW and 40kW, and the output torque can be between 200Nm and 600Nm.

[0044] The grouting drill bit 1 and the push rod section 2 are both provided with a hollow inner cavity. The hollow inner cavities of the grouting drill bit 1 and the push rod section 2 are interconnected and connected to the grouting pump 5 and the slurry tank 7 in sequence through the grouting pipe 6. The grouting pipe 6 can also be designed in sections, including a front section 12 and a remaining section, and the two sections are connected by a telescopic elbow. The grouting pipe 6 is reusable.

[0045] like Figure 3 As shown, the device of the present invention places the grouting pipe 6 inside the drill bit, and uses the drill bit to break the soil in the foundation to form a supporting structure, and then injects the grouting liquid into the surrounding of the structure through the drill bit cavity and the grouting hole 8 for solidification, so as to reduce the need to repeatedly insert multiple grouting pipes 6 into the foundation for grouting; after solidification is formed, further expansion and excavation can be carried out in the hole excavated by the original drill bit.

[0046] The front section 12 of the grouting pipe is made of a seamless steel pipe with a diameter of 50 mm or 70 mm. The seamless steel pipe has the advantages of high strength and good corrosion resistance, can ensure the grouting pressure during the grouting process, and improve the stability and durability of the front section 12 of the grouting pipe.

[0047] There are several push rod segments 2, which can be 1m to 5m in length and can be manufactured according to splicing needs; several push rod segments 2 are connected by corresponding slots 9 to form a push rod as a whole that can be loaded and unloaded along the length direction.

[0048] The device also includes an excavation device, which can be a rotary drilling rig or a mechanical Luoyang shovel. The excavation device is easy to operate and can achieve rapid and efficient excavation of the soil, thereby improving construction efficiency and quality.

[0049] The spacing between the grouting holes 8 is 1.5 times the preset grouting penetration range. In clay and silt, due to the finer soil particles and smaller pores, the penetration range of the grouting liquid is usually smaller, generally between 0.5 meters and 2 meters. In sand and gravel, due to the larger soil particles and more pores, the penetration range of the grouting liquid is usually larger, generally between 2 meters and 5 meters, or even further. Under some special geological conditions, such as the presence of groundwater flow or a large amount of organic matter in the soil, the penetration range of the grouting liquid may be limited and needs to be determined through field tests, laboratory tests or numerical simulations. The properties of the grouting material (such as viscosity, setting time) and the grouting process (such as grouting pressure, grouting speed) will also affect the penetration range. For example, using low-viscosity grouting materials and higher grouting pressure can increase the penetration range.

[0050] Example 2 This embodiment differs from embodiment 1 in that: The device of the present invention can also be arranged horizontally and applied to situations where horizontal excavation is carried out after vertical excavation of sand and soil, such as some pipe-roof support or extended excavation at the bottom of a well, as a supplementary solution to vertical excavation.

[0051] The present invention also discloses an original soil foundation construction device based on advance pre-grouting reinforcement, including drilling and grouting equipment; the drilling and grouting equipment includes a grouting drill bit 1, a push rod segment 2, a gear 3, a driving device 4, a grouting pump 5, a grouting conduit 6 and a slurry tank 7; a circumferential cutter head is provided on one side of the grouting drill bit 1, and a slot 9 matching the push rod segment 2 is provided on the other side of the grouting drill bit 1; a grouting hole 8 is provided on the grouting drill bit 1; slots 9 are respectively provided on both sides of the push rod segment 2, the slot 9 on one side corresponds to the slot 9 of the grouting drill bit 1, and the slot 9 on the other side corresponds to the slot 9 of the next push rod segment 2; the push rod segment 2 farthest from the grouting drill bit 1 is provided with an external thread 10, and the push rod segment 2 and the gear 3 are screw-driven; the driving device 4 transmits the rotational force to the gear 3 through a driving connecting rod 13; the driving connecting rod 13 can also adopt a segmented design, and the two ends are hinged by a universal joint, providing more degrees of freedom, facilitating rotational force transmission and construction in narrow curved spaces. The device for horizontal excavation also requires an internal support structure, such as steel sheet piles, concrete retaining walls and surface concrete, to provide internal support for the inner surface of the well during horizontal excavation.

[0052] The grouting drill bit 1 and the push rod section 2 are both provided with a hollow inner cavity, and the hollow inner cavities of the grouting drill bit 1 and the push rod section 2 are interconnected and connected to the grouting pump 5 and the slurry tank 7 in sequence through the grouting conduit 6; the grouting conduit 6 should be provided with slurry holes at intervals along the length direction.

[0053] This embodiment also includes a cyclone pulping machine and special grouting equipment; the special grouting equipment includes a grouting valve, a high-pressure hose and a monitoring instrument; the monitoring instrument includes a pressure gauge, a flow meter and a grouting automatic recorder.

[0054] For grouting flow rates of 10 to 30 cubic meters per hour, a slurry machine with a capacity of 20 to 40 cubic meters per hour can be selected to ensure that the slurry production capacity matches the grouting needs. The cyclone slurry machine can quickly and evenly mix the grouting materials, ensuring the quality and stability of the slurry, thereby improving the efficiency and quality of grouting.

[0055] The grouting valve should have good flow regulation function and be able to be flexibly adjusted within the range of 10 to 30 cubic meters per hour to meet different grouting needs.

[0056] The pressure rating of the high-pressure hose should be higher than the grouting pressure to ensure the safety and durability of the pipeline. Typically, a high-pressure hose with a pressure rating of 20MPa to 30MPa is recommended. High-pressure hoses can withstand high pressures, ensuring smooth delivery of the grouting fluid at high pressure while avoiding safety accidents caused by pipeline rupture.

[0057] The accuracy of pressure gauges and flow meters should meet the requirements of the grouting process. Typically, instruments with an accuracy level of ±1% are selected to ensure measurement accuracy. The range of the pressure gauge and flow meter should be selected based on the grouting pressure and flow rate to ensure the instruments operate within their normal operating range, improving measurement accuracy and reliability. These monitoring instruments can display grouting pressure and flow in real time, helping operators to adjust grouting parameters promptly and ensure accuracy and controllability of the grouting process. Automatic recorders can record various parameters during the grouting process in detail, providing data support for subsequent analysis and evaluation, helping to optimize the grouting plan and improve project quality.

[0058] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment alone, but also includes any changes, replacements and other implementation methods that can be easily thought of by any person skilled in the art within the technical scope disclosed by the present invention. Although the embodiments of the present invention have been shown and described, it is understood by those skilled in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A construction method for an undisturbed soil foundation based on advanced pre-grouting reinforcement, characterized in that: The steps include: Drill the original ground soil foundation and fill the soil foundation gaps in the drilled space for pre-reinforcement; The soil foundation around the space to be drilled is pre-reinforced to form a stable stone body, and foundation pit excavation is carried out on the pre-reinforced soil body.

2. The method for constructing an original soil foundation based on advance pre-grouting reinforcement according to claim 1, characterized in that: The pre-reinforcement adopts the form of ground static pressure grouting to pre-grout the original ground soil foundation before excavation.

3. The method for constructing an undisturbed soil foundation based on advance pre-grouting reinforcement according to claim 2, characterized in that: The ground static pressure grouting form is selected from one or more of filling grouting, penetration grouting, compaction grouting and splitting grouting.

4. The method for constructing an undisturbed soil foundation based on advance pre-grouting reinforcement according to claim 2, characterized in that: The grouting material for the pre-grouting is selected from inorganic grouting material or organic grouting material.

5. The method for constructing an undisturbed soil foundation based on advanced pre-grouting reinforcement according to claim 4, characterized in that: The inorganic grouting material is one or more of cement-calcium chloride solution, cement-triethanolamine-calcium chloride solution, ultrafine cement, wet-ground ultrafine cement, paste cement, cement-water glass double slurry, clay-bentonite slurry, water glass-calcium chloride slurry, water glass-sodium aluminate slurry, steel fiber, glass fiber, and basalt fiber; the organic grouting material is one or more of pulp waste liquid-sodium dichromate slurry, pulp waste liquid-ammonium persulfate slurry, urea-formaldehyde resin-sulfuric acid slurry, urea-formaldehyde-ferric oxide slurry, water-soluble polyurethane slurry, non-water-soluble polyurethane slurry, and polyester fiber.

6. A device for constructing an undisturbed soil foundation based on advanced pre-grouting reinforcement according to any one of claims 1 to 5, characterized in that: The invention comprises a drilling grouting device; the drilling grouting device comprises a grouting drill bit (1), a push rod section (2), a gear (3), a driving device (4), a grouting pump (5), a grouting pipe (6) and a slurry tank (7); a ring cutter head is provided on one side of the grouting drill bit (1), and a slot (9) matching with the push rod section (2) is provided on the other side of the grouting drill bit (1); a grouting hole (8) is provided on the grouting drill bit (1); slots (9) are provided on both sides of the push rod section (2), and the slot (9) on one side is aligned with the slot of the grouting drill bit (1). (9), and the other side slot (9) corresponds to the slot (9) of the next push rod section (2); the push rod section (2) farthest from the grouting drill bit (1) is provided with an external thread (10), and the push rod section (2) and the gear (3) are screw-driven; the driving device (4) rotates the gear (3); the grouting drill bit (1) and the push rod section (2) are both provided with a hollow inner cavity, and the hollow inner cavities of the grouting drill bit (1) and the push rod section (2) are interconnected and connected to the grouting pump (5) and the slurry tank (7) in sequence through the grouting pipe (6).

7. The device for the undisturbed soil foundation construction method based on advance pre-grouting reinforcement according to claim 6, characterized in that: It also includes excavation equipment; the excavation equipment is a rotary drilling rig or a mechanical Luoyang shovel.

8. The device for the undisturbed soil foundation construction method based on advance pre-grouting reinforcement according to claim 6 is characterized in that: There are a plurality of push rod segments (2); the plurality of push rod segments (2) are connected through corresponding slots (9) to form a push rod as a whole that can be assembled and disassembled along the length direction.

9. The device for the undisturbed soil foundation construction method based on advance pre-grouting reinforcement according to claim 6, characterized in that: The spacing between the grouting holes (8) is 1.5 times the preset grouting penetration range.

10. The device for the undisturbed soil foundation construction method based on advance pre-grouting reinforcement according to claim 6, characterized in that: The grouting pipe further comprises a grouting pipe front section (12), and the grouting pipe front section (12) is made of a seamless steel pipe with a pipe diameter of 50 mm or 70 mm.

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