Stress calculation method, device and equipment for soil nailing wall composite structure between side slope piles and storage medium

Abstract

The invention relates to the technical field of side slope engineering, and discloses a side slope inter-pile soil nailing wall composite structure stress calculation method, device and equipment and a storage medium, and the side slope inter-pile soil nailing wall composite structure stress calculation method comprises the following steps: S100: analyzing the shape and size of an inter-pile horizontal soil arch; s200, calculating the load of the anti-slide pile; s300, the load of the soil nailing wall is calculated; and S400, according to the load of the soil nailing wall, a soil nailing anchoring section and a free section are divided. According to the stress calculation method for the soil nailing wall composite structure between the side slope piles, the influence of the soil arch effect on the stress of the soil nailing wall between the piles is considered, on one hand, the influence of the soil arch on the stress distribution of the anti-slide pile and soil nailing wall composite structure can be explained, on the other hand, the arrangement of soil nails can be optimized, and free sections and anchoring sections of the soil nails can be more accurately divided; therefore, construction is optimized, construction efficiency is improved, and construction cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of slope engineering, and particularly relates to a method, device, equipment and storage medium for calculating the force of a combined structure of slope piles and soil nail walls. Background Art

[0002] Anti-slide pile retaining structures are widely used in the cutting high slope engineering of mountain roads. In the design of the soil mass in front of the arch in the cantilever section of the pile, soil nail walls, retaining plates or retaining walls are mostly used for reinforcement. These measures can effectively prevent the further weathering of the rock and soil mass between the piles and prevent the soil mass from collapsing.

[0003] When using a soil nail wall to reinforce the soil mass on the cantilever free face, the horizontal soil arch effect between the piles will have an important impact on the force of the soil nail wall structure and the force of the soil nails themselves. However, the current specifications only make simple provisions on the layout spacing and length of the soil nails, and do not fully consider the influence of the horizontal soil arch effect on the force of the soil nail wall structure between the piles; designers mostly calculate the force of each part of the soil nail wall between the piles according to the specifications or the experience of the design unit, and design the length of the soil nails.

[0004] Therefore, in the prior art, for the combined structure of slope piles and soil nail walls, those skilled in the art do not fully consider the influence of the horizontal soil arch effect during design, and there are large errors in the force of the soil nail wall between the piles and the accuracy of the division of the free section and the anchorage section of the soil nails. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that those skilled in the art do not fully consider the influence of the horizontal soil arch effect on the combined structure of slope piles and soil nail walls during design. The purpose is to provide a method, device, equipment and storage medium for calculating the force of a combined structure of slope piles and soil nail walls to solve the above problems.

[0006] The present invention is achieved by the following technical solutions: In a first aspect, the present invention provides a method for calculating the force of a combined structure of slope piles and soil nail walls, including the following steps: S100: Analyze the shape and size of the horizontal soil arch between the piles, and determine the range of the unstable soil mass area in front of the arch between the piles; S200: Calculate the load of the soil nail wall between the piles based on the horizontal soil arch effect; S300: Divide the anchorage section and the free section of the soil nails according to the shape and size of the horizontal soil arch between the piles; S400: Based on S100 - S300, determine the length of the soil nails; S500: After the soil nails reinforce the soil mass between the piles and in the unstable area in front of the arch, consider the action of the soil mass in front of the arch between the piles, and calculate the load on the anti-slide piles.

[0007] In a possible design, step S100 includes the following steps: S110: Draw a horizontal soil arch along the connection line of two adjacent anti-slide piles. S120: Obtain the central arch height, inner-edge arch height, and outer-edge arch height of the horizontal soil arch based on the pile cross-section width and the clear distance between piles.

[0008] In a possible design, in step S120, the central arch height h , inner-edge arch height h 1, and outer-edge arch height h 2 are obtained according to the following formula: ; where a is the pile cross-section width, d is the clear distance between piles.

[0009] In a possible design, step S200 includes the following steps: S210: Calculate the active earth pressure generated by the soil mass in front of the arch between piles. S220: Calculate the remaining sliding force of the soil mass in front of the arch between piles. S230: Take the larger value of the two to obtain the soil nail wall load.

[0010] In a possible design, step S210 includes the following steps: S211: Divide the wedge using the wedge equilibrium method and calculate the active earth pressure through the static equilibrium condition. S212: If the rock and soil mass is cohesionless soil, obtain the active earth pressure according to the following formula E a1 : ; ; ; where G 1 is the self-weight of the first wedge, G 2 is the self-weight of the second wedge; α is the angle between the retaining structure wall back and the horizontal plane, which is an obtuse angle when it is inclined backward, α > 90°; β is the angle between the slope top ground and the horizontal plane; θ is the angle between the soil rupture surface and the horizontal plane; H 1 is the vertical height of the slope; H 2 is the length of the potential rupture surface; γ is the soil unit weight; φ is the soil internal friction angle; δ is the soil friction angle against the wall back; S213: If the rock and soil mass is cohesive soil, the active earth pressure is obtained according to the following formula E a2 : ; where L 1 is the length of the bottom surface of the potential rupture plane; L 2 is the length of the vertical plane of the potential rupture plane; c is the cohesion of the soil mass; for other parameters, refer to step S212.

[0011] In a possible design, in step S232, when the slope is soft rock or weathered and fractured rock, the active earth pressure is obtained by substituting the comprehensive internal friction angle into the active earth pressure calculation formula: Comprehensive internal friction angle where θ R is the angle between the rock rupture plane and the horizontal direction; γ R is the unit weight of the rock mass; c R is the cohesion of the rock mass; φ R is the internal friction angle of the rock mass.

[0012] In a possible design, step S300 includes the following steps: S310: Calculate the slope rupture angle and obtain the position of the bottom surface of the potential rupture plane through the slope rupture angle; S320: If the soil nail intersects with the arch axis of the horizontal soil arch, establish a coordinate system and divide the anchored section and free section of the soil nail by the following formula: ; where L f is the length of the free section of the soil nail, a is the width of the pile cross-section; b is the height of the pile cross-section; θ i is the angle between the soil nail and the horizontal plane; α i is the angle between the shotcrete and anchor surface and the vertical direction; l is the distance from the top connection line of the pile to the top line of the shotcrete and anchor surface; z is the height of the soil nail from the top of the soil nail wall; h 0 is the vertical height or length of the vertical plane formed by the arch axis of the horizontal soil arch above the rupture plane; x is the distance of the soil nail from the mid-span section between piles; S330: If the soil nail does not intersect with the arch axis of the horizontal soil arch, divide the anchored section and free section of the soil nail according to the slice method.

[0013] In a possible design, in S400, the soil nail length is calculated based on the following formula: ； In the formula, L is the soil nail length, L f is the free section length of the soil nail, L a is the anchorage section length of the soil nail.

[0014] In a possible design, S500 includes the following steps: S510: Obtain slices according to the transmission coefficient method; S520: Obtain the anti-slide pile load according to the calculation formula where, is the actual load on the anti-slide pile considering the action of the soil between piles, E is the width of the pile section, a is the clear distance between piles, d is the remaining sliding force at the slice at the back of the pile, E n-1 is the remaining sliding force at the slice between piles. E n is the remaining sliding force at the slice between piles.

[0015] In a possible design, when the slice between piles is a sliding block, E n-1 >E n ; when the slice between piles is an anti-sliding block, E n-1 < E n .

[0016] In a second aspect, the present invention provides a device for calculating the force of a soil nail wall composite structure, including: An acquisition unit: Analyze the shape and size of the horizontal soil arch between piles, and determine the range of the pre-arch unstable soil mass area; A soil nail wall load calculation unit: Calculate the load of the soil nail wall between piles based on the horizontal soil arch effect; A soil nail division unit: Divide the anchorage section and the free section of the soil nail according to the shape and size of the horizontal soil arch between piles; A soil nail length calculation unit: Determine the soil nail length; An anti-slide pile load calculation unit: After the soil nails reinforce the soil between piles and the pre-arch unstable area soil mass, calculate the load on the anti-slide pile considering the action of the soil in front of the arch between piles.

[0017] In a third aspect, the present invention provides a device that executes the method for calculating the force of the slope pile-interval soil nail wall composite structure.

[0018] In a fourth aspect, the present invention provides a storage medium, on which instructions are stored. When the instructions are run on a computer, the computer is made to execute the method for calculating the forces on the combined structure of slope piles and soil nails between piles.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. The method for calculating the forces on the combined structure of slope piles and soil nails between piles takes into account the influence of the soil arch effect on the forces on the soil nails between piles. On the one hand, it can explain the influence of the soil arch on the force distribution of the combined structure of anti-slide piles + soil nails, and on the other hand, it can optimize the layout of the soil nails, and more accurately divide the free section and the anchored section of the soil nails, thereby optimizing the construction, improving the construction efficiency, and reducing the construction cost; 2. Based on theoretical analysis, the method for calculating the forces on the combined structure of slope piles and soil nails between piles gives relevant calculation formulas, which are convenient for the staff to carry out relevant calculations, and can estimate the design value of the active earth pressure of the soil nails between piles, and is easy to apply; 3. It can be applied to cut slopes such as hard or stiff cohesive soils, cemented or weakly cemented silts, sands, gravels, soft rocks, and weathered and broken rock formations, which are easy to form soil arches between piles and are suitable for soil nail reinforcement, with a wide range of applications and good practicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts. In the drawings: Figure 1 is a schematic plan view of the soil arch effect between piles and the force analysis of the soil nail wall structure.

[0021] Figure 2 is a schematic top view structure of the combined structure of slope piles and soil nails between piles.

[0022] Figure 3 is Figure 2 a cross-sectional schematic diagram of

[0023] Figure 4 is a schematic diagram of the forces on the soil nails between piles when considering the horizontal soil arch effect.

[0024] Figure 5 When the rock and soil mass is cohesionless soil, Figure 4 is a schematic diagram of the forces on the soil wedge behind the

[0025] Figure 6 When the rock and soil mass is cohesive soil,Figure 4 Schematic diagram of the force on the soil wedge behind the wall

[0026] Figure 7 Schematic diagram of the segmented soil nails between piles

[0027] Figure 8 Schematic flow diagram of the force calculation method for the combined structure of soil nail wall between piles in a slope

[0028] Figure 9 Schematic diagram of the structure of the simulated slope in Example 2

[0029] Figure 10 Schematic diagram of the calculation of the earth pressure of the soil nail wall between piles in Example 2

[0030] Figure 11 Simplified diagram for the design calculation of the soil nail wall in Example 2 Detailed implementation manners

[0031] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in combination with the embodiments and the accompanying drawings. The illustrative embodiments and descriptions thereof of the present invention are only used to explain the present invention and do not limit the present invention

[0032] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is obvious to those of ordinary skill in the art that the present invention does not have to be implemented with these specific details. In other embodiments, well-known structures, circuits, materials or methods are not specifically described in order to avoid obscuring the present invention

[0033] Throughout the specification, the reference to "one embodiment", "embodiment", "one example" or "example" means that the specific features, structures or characteristics described in connection with the embodiment or example are included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment", "embodiment", "one example" or "example" appearing throughout the specification do not necessarily all refer to the same embodiment or example. In addition, the specific features, structures or characteristics can be combined in any appropriate combination and / or sub-combination in one or more embodiments or examples. In addition, those of ordinary skill in the art should understand that the drawings provided herein are for illustrative purposes only and the drawings are not necessarily drawn to scale. The term "and / or" used herein includes any and all combinations of one or more of the related listed items

[0034] In the description of the present invention, the orientation or positional relationship indicated by terms such as "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is 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 construed as a limitation on the protection scope of the present invention.

[0035] Embodiment 1:

[0036] According to the research of the prior art, the soil arching effect between piles is closely related to the stability of the soil between piles. When the pile spacing meets a certain range, the pile-soil interaction can be effectively exerted to form the soil arching effect. At the same time, in the prior art, those skilled in the art have analyzed the formation mechanism through model tests and numerical simulations, and generally believe that the soil arch is a compacted arch body, which is in an elastic state relative to the surrounding soil. Specifically, referring to Figure 1 , from the outside to the inside, the soil between piles is sequentially distributed in the unstable area, the compacted area, and the stable area. Among them, the compacted area is arched, that is, the soil arch; the soil between piles is divided into the soil in front of the arch in the unstable area, the compacted arch body in the soil arch, and the soil behind the arch in the stable area.

[0037] Further explanation in combination with the operation of the soil nail wall between piles: Construction of anti-slide piles; Excavate the soil in front of the piles in layers to set soil nails and soil nail walls.

[0038] Among them, after the soil in front of the piles is excavated, due to the unloading effect, the soil on the temporary free surface between piles will produce outward extrusion and collapse phenomena in the unstable area. The anti-slide piles have been constructed and provide support for the arch feet. Due to the existence of the support arch feet, uneven displacement or relative displacement will occur between the soil masses on the back of the piles under the action of the landslide thrust; when the displacement reaches a certain shear strength of the soil, the soil particles will exert a wedging effect and form a compacted area on the back of the piles, and then form a soil arch. When the soil arch is formed, the soil behind it will be in a stable state. At the same time, during the process of excavating the soil in front of the piles in layers, an increasing landslide thrust or soil pressure is continuously generated. At this time, the soil arch is gradually compacted from top to bottom and transfers the slope soil pressure or landslide thrust to the pile body.

[0039] For the unstable area, the soil in front of the arch in the unstable area is reinforced by soil nails, and it is tightly connected to the compacted arch body and the soil behind the arch in the stable area, so that the original unstable area becomes a stable area. At this time, the compacted arch body and the soil behind the piles play the role of the anchorage section of the soil nails.

[0040] According to the specification "Code for Design of Retaining Structures of Railway Subgrade (TB10025–2019)", anti-slide piles are designed as flexural members. The total horizontal displacement at the pile top should be less than 1 / 100 of the length of the cantilever section (of the anti-slide pile), and should not be greater than 100 mm. Based on this, it can be known that in actual slope reinforcement projects, anti-slide piles can produce bending deformations or rotations allowed by the specifications. As Figure 1 shown, since the soil arch is a compacted elastic arch, when a certain deformation occurs in the pile body that serves as the support of the arch foot, it will push and compress the stable soil mass in front of the arch between the piles that has been reinforced by soil nails. At this time, the soil mass in front of the arch will play an anti-slide role to share the total remaining sliding force of the slope.

[0041] Based on the above pile-soil interaction and soil arch formation mechanism, this embodiment proposes a method for calculating the forces on the combined structure of slope pile-intermediate soil nail walls. The method for calculating the forces on the combined structure of slope pile-intermediate soil nail walls takes into account the influence of the soil arch effect on the forces on the pile-intermediate soil nail walls. On the one hand, it can explain the influence of the soil arch on the force distribution of the anti-slide pile + soil nail wall combined structure, and on the other hand, it can optimize the layout of the soil nails, and more accurately divide the free section and the anchored section of the soil nails, thereby optimizing the construction, improving the construction efficiency, and reducing the construction cost.

[0042] As Figure 8 shown, a method for calculating the forces on the combined structure of slope pile-intermediate soil nail walls according to the present invention includes the following steps: S100: Analyze the shape and size of the horizontal soil arch between the piles, and determine the range of the unstable soil mass area in front of the arch between the piles; S200: Calculate the loads on the pile-intermediate soil nail walls based on the horizontal soil arch effect; S300: Divide the anchored section and the free section of the soil nails according to the shape and size of the horizontal soil arch between the piles; S400: Based on S100 - S300, determine the length of the soil nails; S500: After the soil nails reinforce the soil mass in the unstable area between the piles and in front of the arch, calculate the loads on the anti-slide piles considering the action of the soil mass in front of the arch between the piles.

[0043] In the method for calculating the forces on the combined structure of slope pile-intermediate soil nail walls, for step S100, based on the pile spacing between two adjacent anti-slide piles, the shape and size of the corresponding soil arch are obtained, which is convenient for dividing the area where the soil mass between the piles is located, and also provides a basis for subsequent calculations.

[0044] For the soil between piles, its acting force is borne by the anti-slide piles and the soil nail wall respectively. The specific force distribution is calculated through step S200 and step S500 respectively, so that the force values of both can be obtained separately and it is also convenient to compare the force distribution. Further, based on step S200, the lengths of the anchored section and the free section of the soil nails are divided according to the soil nail wall load to optimize the layout of the soil nails. Then, according to the lengths of the anchored section and the free section of the soil nails respectively, the length of the soil nails can be obtained.

[0045] Specifically, for step S100, both the current design standards and research results believe that the horizontal soil arch is symmetric about the mid-span section. Without considering the shape change of the soil arch along the pile length direction, it can be simplified as a plane problem. Then step S100 includes the following steps: S110: Connect adjacent two anti-slide piles and draw a horizontal soil arch; S120: Obtain the central arch height, inner edge arch height and outer edge arch height of the horizontal soil arch according to the pile cross-section width and the clear distance between piles of the anti-slide piles.

[0046] Among them, for the shape of the soil arch, according to the local standard of Chongqing, "Design Standard for Geological Disaster Prevention and Control Engineering" (DBJ50 / T - 029 - 2019), as Figure 2 shown, when looking down, the soil arch is set as an isosceles right triangle. Among them, Figure 2 in, F max is the maximum value of the landslide thrust, taking the maximum value among the natural condition, rainstorm condition and earthquake condition.

[0047] For step S110, as Figure 2 shown, let the adjacent two anti-slide piles be pile Z 1 and pile Z 2 respectively. Among them, the pile back of pile Z 1 has an axis O 1, an inner edge A 1 and an outer edge B 1, and the pile back of pile Z 2 has an axis O 2, an inner edge A 2 and an outer edge B 2. Therefore, a horizontal soil arch Z 1 and pile Z 2 form a horizontal soil arch A 1 AA 2 O 2 B 2 BB 1 O 1 A 1, among which, the central arch height of the horizontal soil arch is set as the axis O 、inner edge A and outer edge BTherefore, A 1 AA 2 is the inner edge line of the arch, O 1 OO 2 is the arch axis line, B 1 BB 2 is the outer edge line of the arch.

[0048] Based on the "Design Standard for Geological Disaster Prevention and Control Engineering" (DBJ50 / T - 029 - 2019), then A 1 AA 2, B 1 BB 2 are both isosceles right - angled triangles.

[0049] Furthermore, let the shotcrete - anchored surface be M 1, and the mid - point of the shotcrete - anchored surface be C , C The projection point of point on the connection line at the pile - setting position A 1 A 2 is D , D This point is also the mid - point of the connection line at the pile - setting position A 1 A 2, then CD is the distance between the shotcrete - anchored surface and the connection line at the pile - setting position A 1 A 2. Let its length be l . Furthermore, let the cross - section width of the (anti - slide) pile be a , the height be b , and the clear distance between piles be d . Based on this, step S130 is carried out to obtain the central arch height, inner - edge line arch height, and outer - edge line arch height of the horizontal soil arch.

[0050] Preferably, in step S120, the central arch height h , inner - edge line arch height h 1 and outer - edge line arch height h 2 are obtained according to the following formula: ; where a is the cross - section width of the pile, d is the clear distance between piles.

[0051] On the basis of Figure 2 make its cross - section diagram, that is Figure 3 , where the soil mass has a potential sliding surface. Let the intersection point of the potential sliding surface and the shotcrete - anchored surface be T , the intersection point with the anti - slide pile be F , the intersection point with the soil arch axis line be O＇ , the intersection point of the potential sliding surface be K , the vertex of the shotcrete - anchored surface be C , the vertex of the back of the anti - slide pileD , the vertex of the axis of the soil arch O .

[0052] Among them, the vertex of the shotcrete and anchor surface C , the vertex of the back of the anti-slide pile D and the vertex of the axis of the soil arch O correspond to Figure 2 the midpoint of the shotcrete and anchor surface in C , C the projection point of the point on the connecting line at the pile - setting position A 1 A 2 D and the central arch height axis of the horizontal soil arch O , so the same symbols are used to represent them.

[0053] Based on this, the central arch height of the soil arch h , that is, the axis of the arch, corresponds to Figure 3 in OO' . At the same time, as Figure 3 shown, the inner - edge arch height h 1 is located on the left side of OO' , and the outer - edge arch height h 2 is located on the right side of OO' .

[0054] For step S200, when considering the horizontal soil arch effect, the force on the soil nail wall is the active earth pressure or the remaining sliding force generated by the soil mass in front of the arch between piles, and the larger value of the two is taken. Therefore, it is necessary to calculate the active earth pressure and the remaining sliding force generated by the soil mass in front of the arch between piles respectively. That is, step S200 includes the following steps: S210: Calculate the active earth pressure generated by the soil mass in front of the arch between piles; S220: Calculate the remaining sliding force of the soil mass in front of the arch between piles S230: Take the larger value of the two to obtain the load of the soil nail wall.

[0055] Specifically, for step S210, the active earth pressure generated by the soil mass in front of the arch between piles can be calculated according to the classical Coulomb earth pressure theory. When not considering the soil arch effect, the load on the soil nail wall can be directly calculated according to the "Code for Design of Highway Subgrade (JTGD30 - 2015)". But when considering the soil arch effect, the wedge - body equilibrium method is used for calculation; as Figure 4 shown, the soil mass has a potential sliding surface and a soil rupture surface. Let the intersection point of the potential sliding surface and the shotcrete and anchor surface be T , the intersection point with the anti - slide pile be F , the intersection point with the axis of the soil arch be O＇ , and the vertex of the potential sliding surface be K ; the potential rupture surface is inclined, its lower end intersects with T point, and its upper end intersects with the soil mass at point G ; the vertex of the shotcrete and anchor surface isC , the vertex of the soil arch axis is O , the intersection surface of the soil arch axis and the potential rupture surface is S , O 1 and O 1 ＇ are the assumed soil arch axes O 1 O 1 ＇ of the two end points. The soil arch axis O 1 O 1 ＇ is the case where it does not intersect with the soil rupture surface TG .

[0056] Among them, Figure 3 and Figure 4 , some end points, such as the intersections of the potential slip surface and each structure, etc., correspond to each other, so the same symbols are used to represent them.

[0057] Assume that the soil nail wall body (i.e., the shotcrete and anchor surface mentioned above) is a rigid body. When the wall CT slides or rotates around the wall toe and overturns, it will cause the soil wedge CTG behind the wall to CT be damaged, specifically sliding and damaging downward along the wall back TG and through the potential rupture surface. At the moment of damage, the wedge CTG is in the limit equilibrium state. Through the static equilibrium conditions, the active earth pressure on the soil nail wall surface can be solved.

[0058] Based on this, when considering the soil arch effect, assume that the soil arch axis OO ' intersects with the soil rupture surface TG at point S , then the active earth pressure borne by the soil nail wall is generated by the strip CTSO , and the active earth pressure of the strip CTSO can be calculated in step S310 。

[0059] Specifically, step S210 includes the following steps: S211: Divide the wedge by the wedge equilibrium method and calculate the active earth pressure through the static equilibrium conditions; S212: If the rock and soil body is cohesionless soil, obtain the active earth pressure according to the following formula E a1 : ; ; ; Among them, G 1 is the self-weight of the first wedge body, G 2 is the self-weight of the second wedge body; α is the angle between the back of the retaining structure and the horizontal plane, which is an obtuse angle when it is inclined backward, α > 90°; β is the angle between the slope top ground and the horizontal plane; θ is the angle between the soil rupture surface and the horizontal plane; H 1 is the vertical height of the slope; H 2 is the length of the potential rupture surface; γ is the soil unit weight; φ is the soil internal friction angle; δ is the friction angle of the soil against the back of the wall; S213: If the rock and soil mass is cohesive soil, the active earth pressure is obtained according to the following formula E a2 : ; Among them, L 1 is the length of the bottom surface of the potential rupture surface; L 2 is the length of the vertical plane of the potential rupture surface; c is the soil cohesion; for the remaining parameters, refer to step S212.

[0060] Based on this, for non-cohesive soils such as weakly cemented sandy soils and gravelly soils, and for cohesive soils such as hard plastic or hard clayey soils, cemented or weakly cemented silty soils, due to the different viscosities of the soil masses, the force conditions of the soil wedges are different. For specific details, refer to Figure 5 and Figure 6 , so they are calculated separately to obtain more accurate results.

[0061] Among them, Figure 5 in Ψ 1 is the angle between the direction of the active earth pressure of non-cohesive soil against the back of the wall and the vertical plane; δ 1 is the friction angle of non-cohesive soil against the back of the wall; φ 1 is the internal friction angle of non-cohesive soil; θ 1 is the rupture angle of the non-cohesive soil slope.

[0062] Figure 6 in Ψ 2 is the angle between the direction of the active earth pressure of cohesive soil against the back of the wall and the vertical plane;δ 2 is the friction angle of cohesive soil against the wall back; φ 2 is the internal friction angle of cohesive soil; θ 2 is the rupture angle of cohesive soil slope.

[0063] In a possible implementation, in step S212, when the slope is soft rock or weathered and fractured rock, the active earth pressure is obtained by substituting the comprehensive internal friction angle into the active earth pressure calculation formula: Comprehensive internal friction angle , where θ R is the angle between the rock mass rupture surface and the horizontal direction; γ R is the unit weight of rock mass; c R is the cohesion of rock mass; φ R is the internal friction angle of rock mass.

[0064] Based on this, according to engineering experience, the active earth pressure is calculated through the comprehensive internal friction angle to simplify the calculation and quickly and accurately calculate the active earth pressure.

[0065] For step S220, as Figure 4 shown, when considering the soil arch effect, the remaining sliding force on the wall surface of the soil nail wall between piles is generated by the soil mass within the potential sliding surface. Due to the existence of soil arches between piles, the landslide thrust behind the arch is transmitted to the anti-slide piles through the arch body and the arch feet. At this time, the soil nail wall between piles only bears the remaining sliding force of the soil mass in front of the arch, that is, the remaining sliding force generated by the strip OCTO ', and its magnitude can be calculated by the method of slices.

[0066] Based on this, the active earth pressure and the remaining sliding force generated by the soil mass in front of the arch between piles are calculated through steps S210 and S220 respectively, and the larger one is taken to complete step S230.

[0067] For step S300, step S300 includes the following steps: S310: Calculate the slope rupture angle and obtain the position of the bottom surface of the potential rupture surface through the slope rupture angle; S320: If the soil nail intersects with the arch axis of the horizontal soil arch, establish a coordinate system and divide the anchored section and the free section of the soil nail by the following formula: ; where L f is the length of the free section of the soil nail, a is the width of the pile section; b is the height of the pile section; θi is the angle between the soil nail and the horizontal plane; α i is the angle between the shotcrete and anchor surface and the vertical direction; l is the distance from the top connection line of the piles to the top line of the shotcrete and anchor surface; z is the height of the soil nail from the top of the soil nail wall; h 0 is the vertical height or length of the upper part of the vertical plane formed by the axis of the horizontal soil arch on the rupture surface; x is the distance of the soil nail from the mid-span section between the piles; S330: If the soil nail does not intersect with the axis of the horizontal soil arch, divide the anchored section and the free section of the soil nail according to the slice method.

[0068] Among them, in step S310, as Figure 4 shown, when considering the horizontal soil arch effect, when the soil nail reinforces the soil in front of the arch, the potential rupture surface OST is a broken line, where OS section is located on the central axis of the soil arch, ST section is located on the soil rupture surface without considering the soil arch between the piles. For the ST section position, it can be solved by calculating the slope rupture angle θ according to the existing specifications.

[0069] Specifically, for the OS section, as Figure 7 shown, if the soil nail layout intersects with the axis of the soil arch first, then take the midpoint A 1 A 2 connection line (i.e., the connection line at the pile setting position in Figure 2 ) as the origin to establish a coordinate system, A 1 A 2) (i.e., the midpoint of the connection line at the pile setting position D (i.e., the midpoint of the connection line A 1 A 2 D ) as the origin, X axis, Y axis, Z axis directions are as Figure 7 shown, where Z the axis direction is positive with vertically downward.

[0070] Let the soil nail MN intersect with the CT section at point M 1, and the soil nail MN intersect with the axis of the soil arch at point N 1, where the coordinate value of point M 1 is ( x , y , z ), and the point N1 For safety reasons, the central axis of the soil arch can be assumed to be the boundary between the anchoring area and the non-anchoring area during design, that is, Figure 7 Points in N 1. Assume that the angle between the soil nail and the horizontal plane is θ i , the angle between the spray anchor surface and the vertical direction is α i , pile top A 1 A The distance from the connecting line 2 to the top line of the spray anchor surface is l . Soil nailing MN Total length L , soil nails are composed of free segments MN 1 and anchoring section N 1 N The lengths are L f , L a , that is, L = L f +L a .

[0071] The potential fracture surface is obtained by step S310 ODB The soil nails can be divided into two categories: one is the soil nails that are close to the potential fracture surface. ODB of BD The other type is the intersection with the potential rupture surface. ODB of OD For the former, the soil nail anchoring section and the free section are divided by step S320, and for the latter, the soil nail anchoring section and the free section are divided by step S330. Specifically, the calculation can be performed according to the relevant provisions of the specification "TB10025-2019 Railway Roadbed Support Structure Design Specification".

[0072] For step S400, the soil nail length is calculated based on the following formula: ； In the formula, L is the soil nail length, L f is the free length of soil nail, L a is the length of the soil nail anchoring section.

[0073] The length of the free section of the soil nail and the length of the anchoring section of the soil nail are calculated in step S300, and the sum of the two is the length of the soil nail.

[0074] For step S500, the existing specifications use the transfer coefficient method (slice method) for calculation. The calculated load borne by a single anti-slide pile is the remaining sliding force or earth pressure within the center spacing range of half of the anti-slide piles on its left and right sides. Taking Figure 2 as an example, pile Z 2 bears CC all the sliding loads within the range of

[0075] In other words, as Figure 2 shown, after the soil nailing wall is set between the piles, it is equivalent to O 1 O 2 all the sliding loads within the range of (including the area in front of the arch between the piles AA 1 A 2) are jointly borne by the two anti-slide piles (pile Z 1 and pile Z 2) on its left and right.

[0076] Based on this, step S500 includes the following steps: S510: Obtain slices according to the transfer coefficient method; S520: Obtain the anti-slide pile load according to the calculation formula ; wherein, E is the actual load of the anti-slide pile considering the action of the soil between the piles, a is the width of the pile section, d is the net distance between the piles, E n-1 is the remaining sliding force at the slice at the back of the pile; E n is the remaining sliding force at the slice between the piles.

[0077] Combined with Figure 3 , E n is the slice between the piles, that is, the slice Figure 3 in TCDF , E n-1 is the slice at the back of the pile, that is, the slice Figure 3 in DFOO '. And E n and E n-1 are respectively calculated by the slice method and will not be elaborated here. In addition, as Figure 3 shown, a small number of soil nails pass through the potential sliding surfaceBO 1', For safety reasons, the influence of this part of the anchoring force can be ignored when calculating the force on the anti-slide pile.

[0078] It should be noted that when the strip between piles is a sliding block, E n-1 >E n ; when the strip between piles is an anti-sliding block, E n-1 < E n . Based on this, as Figure 3 shown, after setting the soil nails, the soil nails will anchor the strip TCDF and the strip DFOO ' and the soil behind the arch into a whole. Therefore, the actual force E on the anti-slide pile needs to consider the sliding characteristics of the strip between piles TCDF , that is, when the strip TCDF is a sliding block, there is E n-1 >E n ; when the strip TCDF is an anti-sliding block, there is E n-1 < E n .

[0079] In engineering practice, those skilled in the art should confirm the sliding characteristics of the strip TCDF according to the actual situation, and then use the method of slices to calculate E n and E n-1 , and finally substitute them into the calculation formula to obtain the actual force E on the anti-slide pile. In most engineering applications, the strips between piles play an anti-sliding role. Therefore, using a soil nail wall or external wall panels to reinforce the rock and soil between piles is beneficial to reducing the excavation volume and reducing the force on the anti-slide pile body, and optimizing the force of the combined structure.

[0080] Example 2:

[0081] This embodiment provides a hardware device for implementing the force calculation method of the slope soil nail wall combined structure described in Example 1, including: Acquisition unit: Analyze the shape and size of the horizontal soil arch between piles to determine the range of the unstable soil area in front of the arch between piles; Soil nail wall load calculation unit: Calculate the load of the soil nail wall between piles based on the horizontal soil arch effect; Soil nail division unit: Divide the anchored section and free section of the soil nail according to the shape and size of the horizontal soil arch between piles; Soil nail length calculation unit: Determine the length of the soil nail; Anti-slide pile load calculation unit: After the soil between piles and the unstable soil area in front of the arch are reinforced by soil nails, considering the action of the soil between piles and in front of the arch, the load on the anti-slide pile is calculated.

[0082] For the working process, working details and technical effects of the device provided in this embodiment, reference can be made to Embodiment 1, which will not be elaborated here.

[0083] This embodiment provides a device that executes the force calculation method for the combined structure of slope piles and soil nail walls. For the working process, working details and technical effects of the device provided in this embodiment, reference can be made to Embodiment 1, which will not be elaborated here.

[0084] This embodiment provides a storage medium with instructions stored thereon. When the instructions are run on a computer, the force calculation method for the combined structure of slope piles and soil nail walls is executed. The storage medium refers to a carrier for storing data, which may include, but is not limited to, floppy disks, optical discs, hard disks, flash memories, USB flash drives, and / or memory sticks, etc. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0085] This embodiment provides a computer program product that causes a computer to execute the force calculation method for the combined structure of slope piles and soil nail walls when the instructions are run on the computer. Among them, the computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0086] Embodiment 3:

[0087] Based on Embodiment 1, a simulation of engineering practice is carried out to illustrate how the force calculation method for the combined structure of slope piles and soil nail walls is actually applied: Assume that the slope belongs to the mid-hill landform, and the surface covering layer is Quaternary Holocene slope-pluvial ( ), gravelly silty clay, and the maximum thickness revealed by drilling reaches 12m, showing a hard plastic state; the underlying bedrock is the Middle Jurassic Xintiangou Formation ( J 2x ), mudstone and sandstone; the physical and mechanical parameters of the slope rock and soil are shown in Table 1. Since there is a road paved at the top of the cut slope of this section, the slope space for excavation is limited, and a combined structure of piles and soil nail walls is designed for reinforcement. Anti-slide piles are constructed at the slope toe, and soil nail walls are arranged between the piles.

[0088]

[0089] Table 1 Physical and mechanical parameter table of slope rock and soil In this slope reinforcement project, it is planned to use piles with a cross-section of 2m×2.5m, a pile spacing of 6m, and a pile length of 18m. Among them, both the cantilever section and the anchorage section are 9m, and the excavation slope ratio of the soil between piles is 1:0.2. According to the calculation in step S130 of the stress calculation method for the combined structure of soil nails between piles in the slope, the horizontal soil arch height at the center section between piles is 3m. And as Figure 9 shown, for the convenience of calculation, a dividing line is set at the arch axis and at the pile location respectively to divide the potential sliding mass into blocks.

[0090] According to step S200 in the stress calculation method for the combined structure of soil nails between piles in the slope, the load of the anti-slide pile is calculated. Among them, considering the project safety, according to the requirements of the "Highway Subgrade Design Code" and the actual situation of the slope, the safety factor K = 1.2 (rainstorm working condition) is taken. After dividing the blocks as Figure 9 shown, according to step S220, the remaining sliding force of the excavated slope is calculated. The results are shown in Table 2. The remaining sliding force at the wall location (block 11) is 383.2kN / m, and the remaining sliding force at the pile location (block 10) is 475.6kN / m.

[0091]

[0092] Table 2 Calculation Table of Remaining Sliding Force per Unit Width Cross-Section Among them, in Table 2, .

[0093] It can be seen that in this engineering example, blocks 9, 10, and 11 in front of the arch between piles all play an anti-sliding role. Therefore, considering the load on the anti-slide pile with the action of the soil between piles, the calculation is as follows according to step S220: ; According to step S300 in the stress calculation method for the combined structure of soil nails between piles in the slope, the load of the soil nail wall is calculated. Among them, in the example, the included angle between the wall panel and the vertical plane is 11º, the arch height of the horizontal soil arch at the mid-span between piles is 3m, and the schematic diagram of the earth pressure calculation of the soil nail wall between piles is as Figure 10 shown. According to the formula provided in step S300, the friction angle between the soil and the panel can be obtained as δ = 16.67º, and the rupture angle of the soil behind the wall is θ = 46º. The remaining calculation parameters are as Figure 10 and Table 1 shown.

[0094] When considering the soil arch effect, the active earth pressure acting on the wall panel by the sliding wedge body CUOST along the rupture surface TSO in Figure 10 is solved. Calculated according to the formula provided in step S300, the result is E a1 = 142.38kN / m. Due to the soil arch effect, the action force of the blocks behind the arch is not considered. At this time, according toFigure 9 The remaining sliding force acting on the wall panel of the strip blocks (9 - 11) in front of the arch between piles of the potential slip surface shown is solved, and the calculation is shown in Table 3, and the result is T 11 = 0 kN / m. After taking the larger value of the two, when considering the soil arch effect, the load on the wall panel should be taken as the earth pressure, that is, 142.38 kN / m.

[0095]

[0096] Table 3 Calculation Table of the Remaining Sliding Force on the Single - width Section of the Soil in Front of the Arch of the Soil Nailing Wall According to step S400 in the calculation method of the force on the combined structure of the slope soil - nailed wall between piles, in which, as Figure 11 shown, the spacing of the soil nails is 1.0 m×1.3 m, with a total of 6 rows and 5 columns, and the angle between the soil nails and the horizontal plane is 10°. The nail material is selected as φ HRB400 deformed steel bars with a diameter of 25 mm, grouted with M30 cement mortar, and the surface layer uses two - layer @15 cmm φ 8 - mm steel mesh, and the thickness of the sprayed C30 concrete is 20 cm; the vertical steel bars of the outer - layer steel mesh adopt 16 - mm round steel with a length of 45 cm φ

[0097] When considering the soil arch effect, the load of the soil - nailed wall is 142.38 kN / m, and the free section and the anchored section of the soil nails are calculated according to step S410. When not considering the soil arch effect, the load of the soil - nailed wall is 194.39 kN / m, and the free section and the anchored section of the soil nails are calculated according to step S420. Design for these two cases respectively, and list the calculation results in Table 4 for comparison.

[0098]

[0099] Table 4 Comparison Table of the Design Calculation Results of the Soil - Nailed Wall Based on the above calculations and summarizing the results in Table 5, the details are as follows:

[0100] Table 5 Calculation Result Table of the Example When not considering and considering the interaction of the soil between piles, the difference rate of the load on the anti - slide pile reaches 14.57%; the soil - nailed wall between piles is greatly affected by the horizontal soil arch effect, and the difference rate of the load on the wall at only the mid - span section reaches 26.75%, corresponding to a saving of 15.68 in the nail material when considering the horizontal soil arch effect.

[0101] ​It can be seen that considering the horizontal soil arch effect between piles and the action of the soil in front of the arch after soil nailing reinforcement is more conducive to improving the economy of anti-slide pile design compared with the traditional method. According to the calculation method provided in Embodiment 1, when designing the soil nailing wall considering the horizontal soil arch effect, the arch height of the corresponding section is 1.5 m. At this time, the load on the wall panel and the length of the free section of the soil nails will be further reduced, and the number of rows of soil nails that intersect the arch axis first will also increase. Due to space limitations, calculations were not performed for all sections, and the entire soil nailing wall design can be completed according to the calculation method provided in Embodiment 1.

[0102] In summary, considering the influence of the horizontal soil arch effect between piles, when arranging soil nails between piles, differential arrangement can be carried out according to the shape and size of the soil arch. The soil nails should be appropriately densified and lengthened at the part with a large arch height in the middle of the span to further optimize the design and improve the economy of the soil nailing wall design between piles.

[0103] The specific embodiments described above have further elaborated on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. Calculation method for the force on the combined structure of slope piles and soil nails between piles, characterized in that, It includes the following steps: S100: Analyze the shape and size of the horizontal soil arch between piles, and determine the range of the under-stable soil mass area in front of the arch between piles; S200: Calculate the load of the soil nailing wall between piles based on the horizontal soil arch effect; S300: Divide the anchored section and the free section of the soil nail according to the shape and size of the horizontal soil arch between piles; S400: Determine the length of the soil nail based on S100 - S300; S500: After the soil nails reinforce the soil mass in the area between piles and in front of the arch where it is under-stable, calculate the load on the anti-slide pile considering the action of the soil mass in front of the arch between piles.

2. The calculation method for the force on the combined structure of slope piles and soil nails between piles according to claim 1, characterized in that, Step S100 includes the following steps: S110: Connect adjacent anti-slide piles and draw the horizontal soil arch; S120: Obtain the central arch height, inner edge arch height, and outer edge arch height of the horizontal soil arch according to the pile section width and the clear distance between piles of the anti-slide pile.

3. The calculation method for the force on the combined structure of slope piles and soil nails between piles according to claim 2, characterized in that, In step S120, the central arch height is obtained according to the following formula h , the inner edge arch height h 1 and the outer edge arch height h 2: ； Among them, a is the width of the pile cross-section, d is the clear distance between piles.

4. The calculation method for the force on the combined structure of slope piles and soil nails between piles according to any one of claims 1 - 3, characterized in that, Step S200 includes the following steps: S210: Calculate the active earth pressure generated by the soil mass in front of the arch between piles; S220: Calculate the remaining sliding force of the soil mass in front of the arch between piles; S230: Take the larger value of the two to obtain the load of the soil nailing wall.

5. The calculation method for the force on the combined structure of slope piles and soil nails between piles according to claim 4, characterized in that, Step S210 includes the following steps: S211: Divide the wedge body using the wedge equilibrium method, and calculate the active earth pressure through the static equilibrium condition; S212: If the rock and soil mass is cohesionless soil, the active earth pressure is obtained according to the following formula E a1 : ； ； ； Among them, G 1 is the self-weight of the first wedge G 2 is the self-weight of the second wedge; α is the angle between the back of the retaining structure and the horizontal plane, which is an obtuse angle when it is overturned backward, α > 90°; β is the angle between the ground surface at the slope top and the horizontal plane; θ is the angle between the soil rupture surface and the horizontal plane; H 1 is the vertical height of the slope; H 2 is the length of the potential rupture surface; γ is the unit weight of soil; φ is the internal friction angle of soil; δ is the friction angle of soil against the back of the wall; S213: If the rock and soil mass is cohesive soil, the active earth pressure is obtained according to the following formula E a2 : ； Among them, L 1 is the length of the bottom surface of the potential rupture surface; L 2 is the length of the vertical surface of the potential rupture surface; c is the soil cohesion; for the remaining parameters, refer to step S212.

6. The calculation method for the force on the combined structure of slope piles and soil nails between piles according to claim 5, characterized in that, In step S232, when the slope is soft rock or weathered and fractured rock, substitute the comprehensive internal friction angle into the active earth pressure calculation formula to obtain the active earth pressure: Comprehensive internal friction angle , where θ R is the angle between the rock mass fracture surface and the horizontal direction; γ R is the unit weight of the rock mass; c R is the cohesion of the rock mass; φ R is the internal friction angle of the rock mass.

7. The calculation method for the force on the combined structure of slope piles and soil nails between piles according to claim 6, characterized in that, Step S300 includes the following steps: S310: Calculate the slope rupture angle, and obtain the position of the bottom surface of the potential rupture surface through the slope rupture angle; S320: If the soil nail intersects with the arch axis of the horizontal soil arch, establish a coordinate system and divide the anchored section and the free section of the soil nail through the following formula: ； Among them, L f is the free length of the soil nail, L a is the anchored length of the soil nail; a is the width of the pile cross-section; b is the height of the pile cross-section; θ i is the angle between the soil nail and the horizontal plane; α i is the angle between the shotcrete and anchor surface and the vertical direction; l is the distance from the top connection line of the piles to the top line of the shotcrete and anchor surface; z is the height of the soil nail from the top of the soil nail wall; h 0 is the vertical height or length of the vertical plane formed by the axis of the horizontal soil arch above the rupture surface; x is the distance of the soil nail from the mid-span section between the piles; S330: If the soil nail does not intersect with the arch axis of the horizontal soil arch, divide the anchored section and the free section of the soil nail according to the slice method.

8. The force calculation method for the combined structure of slope piles and soil nails between piles according to claim 7, characterized in that, In S400, calculate the length of the soil nail based on the following formula: ； In the formula, L is the length of the soil nail, L f is the free length of the soil nail, L a is the anchored length of the soil nail.

9. The force calculation method for the combined structure of slope piles and soil nails between piles according to claim 8, characterized in that, S500 includes the following steps: S510: Obtain the slices according to the transfer coefficient method; S520: Obtain the anti-slide pile load according to the calculation formula ​ Among them, E is the actual load on the anti-slide pile body considering the action of the soil between piles, a is the width of the pile cross-section, d is the clear distance between piles, E n-1 is the remaining sliding force at the strip block at the pile back; E n is the remaining sliding force at the strip block between piles.

10. The force calculation method for the combined structure of slope piles and soil nails between piles according to claim 9, characterized in that, When the strip block between piles is a sliding block, E n-1 >E n ; when the strip block between piles is an anti-sliding block, E n-1 < E n .

11. A force calculation device for the combined structure of soil nails, characterized in that, It includes: Acquisition unit: Analyze the shape and size of the horizontal soil arch between piles, and determine the range of the under-stable soil mass area in front of the arch between piles; Soil nailing wall load calculation unit: Calculate the load of the soil nailing wall between piles based on the horizontal soil arch effect; Soil nail division unit: Divide the anchored section and the free section of the soil nail according to the shape and size of the horizontal soil arch between piles; Soil nail length calculation unit: Determine the length of the soil nail; Anti-slide pile load calculation unit: After the soil nails reinforce the soil mass in the area between piles and in front of the arch where it is under-stable, calculate the load on the anti-slide pile considering the action of the soil mass in front of the arch between piles.

12. A device, characterized in that, Execute the stress calculation method for the combined structure of the soil nailing wall between piles of the slope as described in any one of claims 1 - 10.

13. A storage medium, characterized in that, Instructions are stored on the storage medium, and when the instructions run on a computer, the computer is made to execute the stress calculation method for the combined structure of the soil nailing wall between piles of the slope as described in any one of claims 1 - 10.

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