Sloping slope supporting method based on grouting steel pipe pile-lattice beam pre-stressed anchor cable

Abstract

The invention belongs to the technical field of slope supporting, discloses a slip-releasing slope surface supporting method based on a grouting steel pipe pile-lattice beam pre-stressed anchor cable, and aims to solve the problem that in an existing supporting system, a grouting steel pipe pile cannot provide enough shear capacity for a soil body around the pre-stressed anchor cable. The method comprises the following steps: (1) slope treatment; (2) surveying and setting out are conducted, and the positions of the pre-stressed anchor cables and the grouting steel pipe piles are determined; the pre-stressed anchor cables and the grouting steel pipe piles are arranged in a staggered mode. (3) pre-stressed anchor cables and grouting steel pipe piles are constructed; the pre-stressed anchor cables and the grouting steel pipe piles are arranged in the rock-soil body in the direction perpendicular to the slope surface of the side slope. And (4) lattice beam construction, wherein each connecting node of the lattice beam corresponds to a pre-stressed anchor cable or a grouting steel pipe pile. By changing the arrangement mode of the grouting steel pipe piles, the grouting steel pipe piles can provide more shear resistance for soil around the pre-stressed anchor cables, and then the stability of slope supporting is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of slope support, and in particular relates to a slope surface support method based on grouting steel pipe piles-lattice beam prestressed anchor cables. Background Art

[0002] Prestressed anchor cable is a commonly used active flexible protection structure for slopes. By drilling holes in the slope rock and soil, anchoring one end of the anchor cable in the stable bedrock layer, and applying tension to the other end, the anchor cable and the sliding rock and soil body can work together. This method can effectively adjust the stress state of the slope rock and soil body and enhance the overall stability of the slope. Prestressed anchor cable is widely used in slope engineering due to its flexible construction and significant effect.

[0003] The main bearing material of the anchor cable is the steel strand, which is made of multiple high-strength steel wires. According to the project requirements, the surface of the steel strand can be galvanized, aluminum alloy or epoxy resin coated to improve its mechanical properties and durability. The steel strand has extremely high axial tensile strength and good deformation capacity, but is relatively weak in shear resistance. Therefore, in actual engineering, relying solely on prestressed anchor cables to resist slope sliding has the following disadvantages:

[0004] 1. Insufficient shear resistance: Prestressed anchor cables mainly resist sliding forces through their high-strength axial tensile properties. However, under the action of shear forces (such as when the slope is affected by external factors such as rain erosion, earthquake loads or top loads), the anchor cables are difficult to provide sufficient shear resistance, resulting in a weakening of the overall anti-sliding performance of the slope.

[0005] 2. Local damage and system failure: Under long-term stress conditions, prestressed anchor cables may suffer local damage due to fatigue and external environmental influences, such as cable breakage or loosening of the anchor end. If these damages are not repaired in time, they will gradually expand inside the anchor cable, eventually weakening the overall bearing capacity of the anchor cable, causing the support system to fail and significantly increasing the risk of slope landslides.

[0006] 3. Environmental conditions have a significant impact: Harsh environments (such as continuous rainfall, earthquakes or construction disturbances) will change the stress state of the prestressed anchor cables, further weaken their shear resistance, reduce the stability of the support system, and make it difficult to effectively maintain slope safety in the long term.

[0007] For the above reasons, when supporting slopes, prestressed anchor cables are usually used in combination with other components to form a slope support system. After grouting, grouting steel pipe piles form a high-strength steel pipe pile body with high rigidity and excellent shear resistance, which can greatly improve the shear resistance of the support system.

[0008] Therefore, the support system combining prestressed anchor cables and grouting steel pipe piles is increasingly being used in slope support. For example, the patent with application number 2023223707011 discloses a reinforced micro steel pipe pile for a micro steel pipe pile-anchor cable support system, comprising a micro steel pipe pile, a cement slurry column coaxially sleeved on the outside of the micro steel pipe pile, the micro steel pipe pile is filled with cement mortar, and also comprises a plurality of reinforcing steel bars pre-buried in the cement slurry column; the reinforcing steel bars are parallel to the micro steel pipe pile, and the plurality of reinforcing steel bars are evenly spaced along the circumference of the micro steel pipe pile, the side walls of the reinforcing steel bars are welded to the side walls of the micro steel pipe pile, and the reinforcing steel bars are located at the sliding surface.

[0009] The patent with application number 2020100157126 discloses a flexible treatment structure for collapsed and high-accumulated slopes and a construction method thereof, which has a slope excavated in stages from top to bottom, and a horseway is provided corresponding to each level of the slope; a plurality of steel pipe piles are arranged along the horseway, and the lower ends of the steel pipe piles pass through the unconformity boundary of the stratum, and the upper ends of the steel pipe piles are exposed on the horseway, and a capping beam combined with the steel pipe piles is cast on the horseway, and a frame beam is arranged on the slope surface, and the lower part of the frame beam is connected to the capping beam on the horseway below through an anchor plate; wherein the anchor plate is fixed to the slope through a plurality of prestressed anchor cables, and the frame beam is fixed to the slope through a plurality of mortar anchor rods.

[0010] For example, the patent with application number 2019102393718 discloses a pressed-in micro steel pipe pile-anchor cable combined earth slope support structure and its construction method, including a number of micro steel pipe piles, pile top crown beams and anchor cables. Each micro steel pipe pile is pressed into the soil by static pressure, and the pile end of the micro steel pipe pile extends below the sliding surface, while the pile top is set above the ground surface; in the same row of micro steel pipe piles, the pile tops of each micro steel pipe pile are connected into one by the same pile top crown beam; and in the same row of micro steel pipe piles, an anchor cable is arranged between two adjacent micro steel pipe piles; the anchoring section of the anchor cable is located below the sliding surface, and the cable head of the anchor cable is locked with the pile top crown beam.

[0011] For example, the patent application number 2020111879179 discloses a composite steel pipe pile foundation pit support structure and a construction method thereof, which comprises a plurality of steel pipe piles arranged vertically and linearly, the bottom of the steel pipe piles is driven into the soil layer, self-compacting concrete is poured in the pipe, and a crown beam is poured on the top of each steel pipe pile to form an integral structure, and a reserved position is provided on the cast crown beam on the side of the steel pipe pile close to the direction of the foundation pit; in the process of excavating the foundation pit layer by layer within the support range surrounded by each steel pipe pile, corresponding to each newly excavated soil layer, a plurality of vertically arranged square rib columns are cast in sections at the reserved position of the crown beam; wherein, after the casting of each section of the square rib column is completed, a horizontally placed waist beam is arranged on the section of the square rib column and close to the direction of the foundation pit, each of the waist beams is provided with a plurality of waist beam anchor holes, an anchor cable or anchor rod is inserted into each waist beam anchor hole, the anchor cable or anchor rod is constructed, and the anchor cable or anchor rod and the waist beam are fastened to the square rib column by an anchor.

[0012] For example, the patent application number 2019106681343 discloses a slope reduction and steel pipe pile anchor coordinated support system, including guardrails, steel pipes, 50mm thick concrete, driven anchors, inserted bars, crown beams, prestressed anchor cables, 100mm thick concrete, steel pipe piles, the main structure in the foundation pit), sewage pipes, monitoring points and precipitation wells; guardrails are set as edge protection facilities around the outside of the foundation pit; the slope reduction section of the foundation pit adopts a multi-level slope structure, and the steel pipe is grouted for the active earth pressure zone of the slope surface of the multi-level slope structure; the graded slope surface Sprayed 50mm thick concrete; The sprayed 50mm thick concrete is welded with steel mesh and inserted rebar structure; The driven ground anchor is the connection structure of the slope steel mesh of the multi-level slope structure, and the functions of the inserted rebar and the driven ground anchor are the same, both of which are to improve the adhesion of the steel mesh to the slope of the multi-level slope structure; The crown beam connects the pile rows formed by the steel pipe piles into a whole, and at the same time provides a tensioning fixed pedestal for the prestressed anchor cable tensioning; The prestressed anchor cable transfers the lateral pressure borne by the crown beam and the waist beam to the stratum, and the prestressed anchor cable is a force transmission component.

[0013] As in the support system composed of grouting steel pipe piles and prestressed anchor cables as exemplified above, the grouting steel pipe piles are vertically implanted into the slope soil, and are arranged on the horseway (or platform) of the slope, while the prestressed anchor cables are arranged along the slope surface. Although the end of the prestressed anchor cable is anchored at the upper end of the grouting steel pipe pile, the grouting steel pipe pile and the prestressed anchor cable are far apart, resulting in the grouting steel pipe pile providing a relatively small shear force to the slope soil. When the shear strength of the slope soil itself changes (such as when the slope is affected by external factors such as rain erosion, earthquake loads or top loads), the prestressed anchor cables are difficult to provide sufficient shear resistance, resulting in a weakening of the overall anti-slip performance of the slope. Summary of the invention

[0014] In order to solve the problem that the grouting steel pipe piles in the existing support system cannot provide sufficient shear resistance for the soil around the prestressed anchor cables, the present invention provides a slope support method based on grouting steel pipe piles-lattice beam prestressed anchor cables. By changing the arrangement of the grouting steel pipe piles, the grouting steel pipe piles can provide more shear resistance for the soil around the prestressed anchor cables. Therefore, when the shear resistance of the soil itself changes, the risk of sliding of the soil around the prestressed anchor cables is greatly reduced, thereby improving the stability of the slope support.

[0015] In order to solve the technical problem, the technical solution adopted by the present invention is:

[0016] A slope support method based on grouting steel pipe piles and lattice beam prestressed anchor cables, characterized by comprising:

[0017] (1) Slope treatment: the slope is gradually reduced to form slope surfaces distributed up and down, and platforms are set between adjacent slope surfaces;

[0018] (2) measuring and laying out to determine the positions of prestressed anchor cables and grouting steel pipe piles; the prestressed anchor cables and the grouting steel pipe piles are arranged in an interlaced manner;

[0019] (3) constructing prestressed anchor cables and grouting steel pipe piles; the prestressed anchor cables and grouting steel pipe piles are arranged in the rock and soil mass in a direction perpendicular to the slope surface;

[0020] (4) Lattice beam construction, wherein the lattice beam is formed by a plurality of transverse beams and a plurality of longitudinal beams arranged in an interlaced manner, and connection nodes are formed at the connection between the transverse beams and the longitudinal beams, and each connection node corresponds to a prestressed anchor cable or a grouted steel pipe pile.

[0021] In some embodiments, cast-in-place piles are horizontally arranged on a platform below the slope surface or on a slope surface of a next level below the slope surface; the positions of the cast-in-place piles correspond to the positions of the prestressed anchor cables and grouting steel pipe piles in the same row, so that the cast-in-place piles can cross with the prestressed anchor cables and grouting steel pipe piles extending into the bearing layer of the rock and soil body to form a cross-consolidation body.

[0022] In some embodiments, during the construction process of the prestressed anchor cables and grouting steel pipe piles in step (3), each prestressed anchor cable and grouting steel pipe pile is constructed from the upper row to the lower row.

[0023] In some embodiments, when grouting is performed on prestressed anchor cables or grouting steel pipe piles, the cast-in-place piles in the same row are simultaneously cast in sections to form a cross-consolidated body.

[0024] In some embodiments, before implanting the anchor cable in any anchor hole in the top row, the pile hole of the bored pile should be constructed, and a protective tube should be implanted in the pile hole to protect the pile hole; before implanting the steel pipe in any steel pipe pile hole in the top row, the pile hole of the bored pile should be constructed, and a protective tube should be implanted in the pile hole to protect the pile hole (to prevent the pile hole of the bored pile from collapsing).

[0025] During the specific implementation process, the pile hole for the cast pile is first drilled and the protective tube is implanted in the pile hole; then the anchor hole and the steel pipe pile hole are drilled in order from the upper row to the lower row; when drilling the anchor hole and the steel pipe pile hole, the protective tube is moved outward so that the protective tube will not hinder the drilling of the anchor hole and the steel pipe pile hole.

[0026] In some embodiments, one end of the protective tube that extends into the pile hole has an end cap, and the other end of the protective tube extends out of the pile hole; after the anchor hole is drilled and before the anchor cable is implanted into the anchor rod, the protective tube is pushed to clean the intersection area between the anchor hole and the corresponding cast-in-place pile; or after the steel pipe pile hole is drilled and before the steel pipe is implanted, the protective tube is pushed to clean the intersection area between the steel pipe pile hole and the corresponding cast-in-place pile.

[0027] In some embodiments, when grouting the prestressed anchor or grouting steel pipe piles, the protective tube is moved outward so that the protective tube does not affect the grouting operation of the prestressed anchor or grouting steel pipe piles; when grouting the prestressed anchor or grouting steel pipe piles, the isolation effect of the end cover allows the poured slurry to simultaneously cast the bored piles in sections, and the synchronously cast in sections bored piles and the prestressed anchor or grouting steel pipe piles form a mutually cross-consolidated body.

[0028] In some embodiments, after the grouting of the prestressed anchor cables or grouting steel pipe piles in the bottom row of the slope is initially set, the protective tube is pulled out, steel bars are inserted into the initially set cross-consolidated body, and concrete is poured into the pile hole to form a cast-in-place pile with steel bars.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The slope support method based on grouting steel pipe piles and lattice beam prestressed anchor cables of the present invention connects the prestressed anchor cables and grouting steel pipe piles on the lattice beam in an interlaced manner, so that the grouting steel pipe piles surround the prestressed anchor cables, and the grouting steel pipe piles surround the prestressed anchor cables. The grouting steel pipe piles are relatively close to the prestressed anchor cables, and after the construction of the grouting steel pipe piles, the surrounding rock and soil bodies can be reinforced to improve the shear resistance of the rock and soil bodies; under the influence of the grouting steel pipe piles, the shear resistance of the rock and soil bodies around the prestressed anchor cables is naturally improved. When the shear resistance of the slope soil body itself changes (for example, in bad weather, etc.), the risk of soil sliding around the prestressed anchor cables is also greatly reduced, thereby improving the stability of the slope support.

[0031] The present invention arranges horizontal cast-in-place piles and simultaneously casts the cast-in-place piles in sections, so that each prestressed anchor cable and each grouting steel pipe pile can form a cross-consolidation body. The "X"-shaped cross-consolidation body is used to further improve the pull-out resistance of the prestressed anchor cable and the grouting steel pipe pile and the anchoring force with the rock and soil.

[0032] The present invention divides the entire cast-in-place pile into two sections: one section forms a cross-consolidation body with each prestressed anchor cable and grouting steel pipe pile, and the other section forms a cast-in-place pile with shear resistance. Thus, the cast-in-place pile with pre-embedded steel bars can be used to further improve the shear resistance of the slope and increase the stability of the slope support. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of an embodiment of a slope support method based on grouting steel pipe piles and lattice beam prestressed anchor cables of the present invention, in which the bearing layer of the slope is distributed along the directions of AB, BC, CD, DE, and DF;

[0034] Figure 2 The invention is a schematic diagram of the connection between the lattice beam and the prestressed anchor cables and the grouting steel pipe piles according to one embodiment. In the schematic diagram, the prestressed anchor cables and the grouting steel pipe piles are arranged in a staggered manner.

[0035] Figure 3 It is a schematic diagram of the top view structure of an embodiment of the lattice beam of the invention;

[0036] Figure 4 A schematic diagram of another embodiment of the connection between the lattice beam and the prestressed anchor cable and the grouting steel pipe pile of the invention;

[0037] Figure 5 It is a partial schematic diagram of the lattice beam of the present invention after being connected with the prestressed anchor cable and the grouting steel pipe pile;

[0038] Figure 6 It is a schematic diagram of the distribution of the anchor hole of the prestressed anchor cable and the cast-in-place pile during drilling of the present invention;

[0039] Figure 7 It is a schematic diagram of the distribution of the grouting steel pipe pile and the cast-in-place pile during grouting and pouring of the present invention;

[0040] Markings in the figure: 1. Slope surface, 2. Prestressed anchor cable, 3. Grouting steel pipe column, 4. Lattice beam, 41. Transverse beam, 42. Vertical beam, 43. Connection node, 5. Cast-in-place pile, 51. Pile hole, 52. Cross consolidation body, 6. Protective tube, 61. End cover. DETAILED DESCRIPTION

[0041] The present invention is further described below in conjunction with embodiments, which are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, other embodiments obtained by ordinary technicians in the field without creative work are all within the scope of protection of the present invention.

[0042] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance; in addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In conjunction with the accompanying drawings, the slope support method based on grouting steel pipe pile-lattice beam prestressed anchor cable of the present invention includes:

[0044] (1) Slope treatment: The slope is gradually reduced to form a slope surface 1 distributed up and down, and a platform (also called a bridleway) is set between adjacent slope surfaces 1; when the slope is treated, the vegetation and soft soil layer on the slope surface should be removed, and the formed slope surface should be leveled.

[0045] (2) Measure and lay out to determine the positions of the prestressed anchor cables 2 and the grouting steel pipe piles 3; the prestressed anchor cables 2 and the grouting steel pipe piles 3 are arranged in a staggered manner. Therefore, the construction positions of the prestressed anchor cables 2 and the grouting steel pipe piles 3 are also arranged in a staggered manner. That is to say, the periphery of the prestressed anchor cables 2 is surrounded by the grouting steel pipe piles 3, and the periphery of the grouting steel pipe piles 3 is surrounded by the prestressed anchor cables 2. In the specific implementation process, the slope support should arrange a suitable number of prestressed anchor cables and grouting steel pipe piles according to the soil structure of the slope to ensure that the prestressed anchor cables and grouting steel pipe piles meet the support requirements.

[0046] (3) Construct prestressed anchor cables 2 and grouting steel pipe piles 3; the prestressed anchor cables 2 and grouting steel pipe piles 3 are arranged in the rock mass in a direction perpendicular to the slope surface 1. Among them, the bottoms of the prestressed anchor cables 2 and grouting steel pipe piles 3 should extend into the bearing layer of the soil mass, which can be understood and comprehended by those skilled in the art. Specifically, the prestressed anchor cable includes a free end and an anchoring section, and the anchoring section of the prestressed anchor cable should extend into the bearing layer of the rock mass; the lower end of the grouting steel pipe pile also needs to extend into the bearing layer of the rock mass, and the lower end of the grouting steel pipe pile should extend into the bearing layer by at least 0.5m.

[0047] Among them, the construction process of prestressed anchor cables and grouting steel pipe piles belongs to the conventional technology in this field. The construction of prestressed anchor cables mainly includes: positioning and setting out (determining the position of prestressed anchor cables described in step (2)) - drilling - cleaning holes - implanting anchor cables (centering) - grouting; and the construction of grouting steel pipe piles mainly includes: drilling positioning - drilling holes with a drilling rig - implanting steel pipe piles - filling gravel - grouting - secondary grouting - grouting to close the hole. Therefore, the specific construction of prestressed anchor cables and grouting steel pipe piles can be understood and understood by those skilled in the art, and will not be repeated here.

[0048] (4) Construction of lattice beams 4, wherein the lattice beams 4 are formed by staggered arrangement of a plurality of transverse beams 41 and a plurality of longitudinal beams 42, wherein connection nodes 43 are formed at the connection between the transverse beams 41 and the longitudinal beams 42, and each connection node 43 corresponds to a prestressed anchor cable 2 or a grouting steel pipe pile 3. That is, the number of connection nodes corresponds to the number of prestressed anchor cables and grouting steel pipe piles, and therefore, the number of connection nodes formed by the transverse beams and longitudinal beams of the lattice beams is determined according to the number and position of the prestressed anchor cables and grouting steel pipe piles.

[0049] Among them, after the construction of the lattice beam 4 is completed, the prestressed anchor cable 2 should be prestressed and anchored. The application of prestress and anchoring of the prestressed anchor cable belong to the existing technology and will not be repeated here. At the same time, the grouting steel pipe pile 3 should be connected to the lattice beam 4. In the specific implementation process, a through hole is reserved on the connection node 43 of the lattice beam 4, and then the hole of the grouting steel pipe pile is closed. The lattice beam 43 is provided with a through hole for the prestressed anchor cable to pass through, so that the prestressed anchor cable can pass through the lattice beam 4 for tensioning, applying prestress and anchoring.

[0050] The present invention connects the prestressed anchor cables and the grouting steel pipe piles on the lattice beam in an interlaced manner, so that the grouting steel pipe piles surround the prestressed anchor cables, and the grouting steel pipe piles surround the prestressed anchor cables. The grouting steel pipe piles are relatively close to the position of the prestressed anchor cables. After the construction of the grouting steel pipe piles, the surrounding rock and soil can be reinforced to improve the shear resistance of the rock and soil; under the influence of the grouting steel pipe piles, the shear resistance of the rock and soil around the prestressed anchor cables is naturally improved. When the shear resistance of the slope soil changes (for example, in bad weather), the risk of soil sliding around the prestressed anchor cables is greatly reduced, thereby improving the stability of the slope support.

[0051] As mentioned in the background technology of this application, in the prior art, the grouting steel pipe piles are all set vertically downward and arranged on the platform or horseway of the slope, while the prestressed anchor cables are arranged in the soil on the slope surface, which results in a relatively long distance between the prestressed anchor cables and the grouting steel pipe piles, and the influence range of the grouting steel pipe piles is not enough to improve the shear resistance of the soil on the slope surface. Therefore, when the shear resistance of the slope soil changes, the soil (rock and soil) around the prestressed anchor cables is prone to the risk of sliding. The present invention changes the arrangement of the grouting steel pipe columns, the grouting steel pipe piles and the prestressed anchor cables are arranged parallel to each other, and the grouting steel pipe piles and the prestressed anchor cables are staggered and connected to the lattice beams, and then the grouting steel pipe piles are used to improve the shear resistance of the rock and soil around the prestressed anchor cables, and finally improve the stability of the slope support.

[0052] In the prior art, in order to improve the stability of slope management, the designed prestressed anchor cables are always set with a safety factor. However, when the slope encounters a harsh environment (such as continuous rainfall, earthquakes or construction disturbances), the shear resistance of the rock and soil inside the rock and soil will be greatly weakened. Since the shear resistance provided by the prestressed anchor cable is poor, even if the strength of the prestressed anchor cable itself remains the same, the rock and soil around the prestressed anchor cable will also slide, which will lead to support failure.

[0053] In some embodiments, cast-in-place piles 5 are arranged horizontally on the platform below the slope surface 1 or on the slope surface 1 of the next level of the slope surface; the positions of the cast-in-place piles 5 correspond to the positions of the prestressed anchor cables 2 and grouting steel pipe piles 3 in the same column, so that the cast-in-place piles 5 can intersect with the prestressed anchor cables 2 and grouting steel pipe piles 3 extending into the bearing layer of the rock and soil body and form a cross-consolidation body 52. ​​That is to say, the horizontally arranged cast-in-place piles 5 can intersect with each prestressed anchor cable 2 and each grouting steel pipe pile 3 in the bearing layer, and each column of prestressed anchor cables 2 and grouting steel pipe piles 3 corresponds to a cast-in-place pile 5. For example, if this level of slope has 5 columns (each column includes staggered prestressed anchor cables and grouting steel pipe piles), then this level of slope is correspondingly arranged with 5 horizontal cast-in-place piles.

[0054] In the specific implementation process, the length and arrangement angle of the prestressed anchor cables and grouting steel pipe piles are first determined so that each prestressed anchor cable and grouting steel pipe pile can penetrate into the bearing layer of the rock and soil body, and finally the horizontal height position of the bored pile is determined according to the specific conditions of the bearing layer of the rock and soil body of the slope. Since the anchoring section of the prestressed anchor cable or the grouting bored pile that is distributed in the same row and closest to the bored pile can intersect with the bored pile, the anchoring sections of the remaining prestressed anchor cables and grouting steel pipe piles can intersect with the bored pile after extension. Therefore, in the specific implementation process, the position where the anchoring section of the prestressed anchor cable at the bottom of the slope surface interacts with the bearing layer of the rock and soil body is the highest position of the bored pile. If the designed length of the anchoring sections and grouting steel pipe piles of each prestressed anchor cable located above cannot intersect with the horizontal cast-in-place piles, the anchoring sections and grouting steel pipe piles of the prestressed anchor cables shall be extended accordingly so that the anchoring sections and grouting steel pipe piles of each prestressed anchor cable can intersect with the horizontal cast-in-place piles.

[0055] In some embodiments, during the construction of the prestressed anchor cables and grouting steel pipe piles in step (3), each prestressed anchor cable 2 and grouting steel pipe pile 3 is constructed from the upper row to the lower row. That is, the uppermost row of prestressed anchor cables and grouting steel pipe piles are constructed first, and after the construction of the upper row of prestressed anchor cables and grouting steel pipe piles is completed, the next row of prestressed anchor cables and grouting steel pipe piles is constructed, and so on and so forth until the row of prestressed anchor cables and grouting steel pipe piles at the bottom of the slope is completed.

[0056] In some embodiments, when grouting the prestressed anchor cable 2 or the grouting steel pipe pile 3, the cast-in-place piles 5 in the same row are cast in sections to form a cross-consolidation body 52. ​​For example, when grouting the prestressed anchor cable on the rightmost side of the top row, the cast-in-place pile on the rightmost side is cast in sections at the same time, and the sections of the cast-in-place pile are cast around the intersection of the prestressed anchor cable (the prestressed anchor cable on the rightmost side of the top row) and the cast-in-place pile to form a cross-consolidation body.

[0057] In some embodiments, before the anchor cable is implanted in any anchor hole in the top row, the pile hole 54 of the cast-in-place pile 5 should be constructed, and the protective tube 6 should be implanted in the pile hole 54 to protect the pile hole 51; before the steel pipe is implanted in the pile hole of any steel pipe pile in the top row, the pile hole 51 of the cast-in-place pile should be constructed, and the protective tube 6 should be implanted in the pile hole 51 to protect the pile hole (to prevent the pile hole of the cast-in-place pile from collapsing). That is to say, the drilling of the cast-in-place pile hole will not affect the drilling of the anchor hole and the steel pipe pile hole.

[0058] In the specific implementation process, the pile hole 51 of the cast pile 5 is firstly drilled and the protective tube 6 is implanted in the pile hole; then the anchor hole and the steel pipe pile hole are drilled in the order from the upper row to the lower row; when drilling the anchor hole and the steel pipe pile hole, the protective tube 6 is moved outward so that the protective tube 6 will not hinder the drilling of the anchor hole and the steel pipe pile hole.

[0059] In some embodiments, the protective tube 6 has an end cap 61 at one end that penetrates into the pile hole 51, and the other end of the protective tube 6 extends out of the pile hole 51; after the anchor hole is drilled and before the anchor cable is implanted into the anchor rod, the protective tube 6 is pushed to clean the intersection area between the anchor hole and the corresponding cast-in-place pile 5; or after the steel pipe pile hole is drilled and before the steel pipe is implanted, the protective tube 6 is pushed to clean the intersection area between the steel pipe pile hole and the corresponding cast-in-place pile. Thus, the driving effect of the end cap 61 at the end of the protective tube 6 is used to clean the broken rock and soil generated during the drilling process (anchor hole or steel pipe pile hole) to prevent the broken rock and soil from occupying the intersection area between the prestressed anchor cable and the grouting cast-in-place pile and the cast-in-place pile, thereby ensuring that the grouting molding quality of the prestressed anchor cable and the grouting steel pipe pile will not be affected.

[0060] In some embodiments, when grouting the prestressed anchor cable 2 or the grouting steel pipe pile 3 is being poured, the protective tube 6 is moved outward so that the protective tube 6 does not affect the grouting operation of the prestressed anchor cable 2 or the grouting steel pipe pile 3; when grouting the prestressed anchor cable 2 or the grouting steel pipe pile 3 is being poured, the isolation effect of the end cover 61 enables the poured slurry to simultaneously pour the cast-in-place piles 5 in sections, and the synchronously poured cast-in-place piles 5 and the prestressed anchor cable 2 or the grouting steel pipe pile 3 form a mutually cross-consolidated body 52.

[0061] In the specific implementation process, when grouting a prestressed anchor cable or a grouting steel pipe pile is performed, the end cover is located between the anchor hole or the pile hole of the steel pipe pile and the pile hole of the grouting steel pipe pile or the anchor hole of the prestressed anchor cable in the same column in the upper and lower rows on the slope surface. The pile hole 51 of the cast-in-place pile is isolated and segmented by the end cover 61. For example, when the prestressed anchor cable on the rightmost side of the top row is cast first, the end cover is located between the anchor hole and the pile hole of the grouting steel pipe pile on the rightmost side of the next row. For another example, when the grouting steel pipe pile on the rightmost side of the top row is cast first, the end cover is located between the pile hole of the steel pipe pile and the anchor hole of the prestressed anchor cable on the rightmost side of the next row. Because the grouting steel pipe piles and the prestressed anchor cables are arranged in an interlaced manner, the anchor holes and steel pipe pile holes in the same column are also arranged crosswise.

[0062] The present invention can realize the segmented pouring operation of the horizontal bored piles through the protective tube (and the end cover at the end), and can also clean up the debris formed during the drilling process of the anchor hole and the steel pipe pile hole, so as to prevent the debris generated by the drilling from affecting the forming quality of the prestressed anchor cable and the grouting steel pipe pile.

[0063] The present invention arranges horizontal cast-in-place piles and simultaneously casts the cast-in-place piles in sections, so that each prestressed anchor cable and each grouting steel pipe pile can form a cross-consolidation body. The "X"-shaped cross-consolidation body is used to further improve the anchoring force of the prestressed anchor cable and the grouting steel pipe pile.

[0064] In the actual construction process, the end cap can only move the debris toward the bottom of the pile hole of the bored pile, so there will inevitably be debris blocks between adjacent cross-consolidation bodies, but the main function of each "X"-shaped cross-consolidation body is to improve the pull-out resistance of the prestressed anchor cable and the grouting steel pipe pile, and also to improve the consolidation force with the rock and soil. Therefore, even if the debris blocks affect the casting quality of this place (the connection between the previous and subsequent castings) (that is, the debris blocks will be locally entrained during the next grouting), it will not affect the improvement of the anchoring force between the prestressed anchor cable and the grouting steel pipe pile and the rock and soil. When encountering harsh environments that reduce the shear resistance of the rock and soil itself, the cross solid bodies can be fully utilized to stabilize the prestressed anchor cable and the grouting steel pipe pile, thereby improving the stability of the slope support.

[0065] In some embodiments, after the grouting of the prestressed anchor cables 2 or grouting steel pipe piles 3 in the bottom row of the slope is initially solidified, the protective tube 6 is pulled out, and steel bars are inserted into the initially solidified cross-consolidation body 52 and concrete is poured into the pile hole, thereby forming a cast-in-place pile with steel bars. In other words, the entire cast-in-place pile 5 is divided into two sections: one section is to form a cross-consolidation body 52 with each prestressed anchor cable 2 and grouting steel pipe pile 3, and the other section is to form a cast-in-place pile with shear resistance. Thus, the cast-in-place piles embedded with steel bars are used to further improve the shear resistance of the slope and increase the stability of the slope. Among them, after the construction of the cast-in-place piles is completed, the ends of the cast-in-place piles are cast and connected to the lattice beams, thereby supporting the lattice beams and further improving the stability of the slope support.

[0066] In the specific implementation process, when the cast-in-place piles 5 are located on the next level slope surface 1, the cast-in-place piles 5 of the previous level should not affect the construction of the prestressed anchor cables 2 and grouting steel pipe piles 3 on the next level slope surface. Therefore, when determining the height position of the cast-in-place piles, they should be staggered with the position of the connection node 43 of the lattice beam 4 on the next level slope surface 1 (i.e., the position of the prestressed anchor cables and grouting cast-in-place piles), which is also conducive to the uniformity of the support at each position of the entire slope support.

[0067] This cycle is repeated to complete the support of each level of slope step by step. That is, after the support of the slope surface of the previous level is completed, the slope surface of the next level will be supported.

Claims

1. A slope support method based on grouting steel pipe piles and lattice beam prestressed anchor cables, characterized in that: include: (1) Slope treatment; The side slope is gradually sloped to form side slope surfaces (1) distributed up and down, and platforms are arranged between adjacent side slope surfaces (1); (2) measuring and laying out to determine the positions of the prestressed anchor cables (2) and the grouting steel pipe piles (3); the prestressed anchor cables (2) and the grouting steel pipe piles (3) are arranged in a staggered manner; (3) constructing prestressed anchor cables and grouting steel pipe piles; the prestressed anchor cables (2) and grouting steel pipe piles (3) are arranged in the rock and soil mass in a direction perpendicular to the slope surface (1); (4) Construction of a lattice beam (4), wherein the lattice beam (4) is formed by a plurality of transverse beams (41) and a plurality of longitudinal beams (42) arranged in an interlaced manner, and a connection node (43) is formed at the connection between the transverse beams (41) and the longitudinal beams (42), and each connection node (43) corresponds to a prestressed anchor cable (2) or a grouting steel pipe pile (3).

2. The slope support method based on grouting steel pipe pile-lattice beam prestressed anchor cable according to claim 1 is characterized in that: Cast-in-place piles (5) are horizontally arranged on a platform below the slope surface (1) or on a slope surface (1) at a lower level of the slope surface; the positions of the cast-in-place piles (5) correspond to the positions of the prestressed anchor cables (2) and the grouting steel pipe piles (3) in the same row, so that the cast-in-place piles (5) can intersect with the prestressed anchor cables (2) and the grouting steel pipe piles (3) extending into the bearing layer of the rock and soil mass to form a cross-consolidation body (52).

3. The slope support method based on grouting steel pipe pile-lattice beam prestressed anchor cable according to claim 1 is characterized in that: During the construction process of the prestressed anchor cables and grouting steel pipe piles in step (3), each prestressed anchor cable (2) and grouting steel pipe pile (3) is constructed in the direction from the upper row to the lower row.

4. The slope support method based on grouting steel pipe pile-lattice beam prestressed anchor cable according to claim 2 is characterized in that: When grouting the prestressed anchor cable (2) or the grouting steel pipe pile (3), the cast-in-place piles (5) located in the same row are simultaneously cast in sections to form a cross-consolidation body (52).

5. The slope support method based on grouting steel pipe pile-lattice beam prestressed anchor cable according to claim 4 is characterized in that: Before the anchor cable is implanted in any anchor hole of the uppermost row, the pile hole (51) of the cast-in-place pile (5) should be constructed, and a protective tube (6) should be implanted in the pile hole (51) to protect the pile hole; before the steel pipe is implanted in any steel pipe pile hole of the uppermost row, the pile hole (51) of the cast-in-place pile should be constructed, and a protective tube (6) should be implanted in the pile hole (51) to protect the pile hole (51).

6. The slope support method based on grouting steel pipe pile-lattice beam prestressed anchor cable according to claim 5 is characterized in that: First, a pile hole (51) of a cast pile (5) is drilled and a protective tube (6) is implanted in the pile hole; then, anchor holes and steel pipe pile holes are drilled in order from the upper row to the lower row; when drilling to form the anchor holes and steel pipe pile holes, the protective tube (6) is moved outward so that the protective tube (6) does not hinder the drilling of the anchor holes and steel pipe pile holes.

7. The slope support method based on grouting steel pipe pile-lattice beam prestressed anchor cable according to claim 6 is characterized in that: The end of the protective tube (6) extending into the pile hole (51) is provided with an end cap (61), and the other end of the protective tube (6) extends out of the pile hole (51); after the anchor hole is drilled and before the anchor cable is implanted into the anchor rod, the protective tube (6) is pushed to clean the intersection area between the anchor hole and the corresponding cast-in-place pile; or after the steel pipe pile hole is drilled and before the steel pipe is implanted, the protective tube (6) is pushed to clean the intersection area between the steel pipe pile hole and the corresponding cast-in-place pile.

8. The slope support method based on grouting steel pipe piles and lattice beam prestressed anchor cables according to claim 7 is characterized in that: When grouting the prestressed anchor cable (2) or the grouting steel pipe pile (3), the protective tube (5) is moved outward so that the protective tube does not affect the grouting operation of the prestressed anchor cable (2) or the grouting steel pipe pile (3); when grouting the prestressed anchor cable or the grouting steel pipe pile, the isolation effect of the end cover (61) enables the poured slurry to synchronously cast the cast-in-place pile (5) in sections, and the synchronously cast-in-section cast-in-place pile (5) and the prestressed anchor cable (2) or the grouting steel pipe pile (3) form a mutually cross-consolidated body (52).

9. The slope support method based on grouting steel pipe pile-lattice beam prestressed anchor cable according to claim 8 is characterized in that: After the grouting of the prestressed anchor cables or grouting steel pipe piles in the lowest row of the slope is initially set, the protective tube (6) is pulled out, and steel bars are inserted into the initially set cross-consolidated body (52) and concrete is poured into the pile hole (51), thereby forming a cast-in-place pile (5) with steel bars.

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