Stress calculation method, device, equipment and storage medium for slope pile-soil nail wall composite structure

Abstract

The present invention relates to the field of slope engineering technology and discloses a force calculation method, device, equipment, and storage medium for a combined structure of soil nailing walls between piles on a slope. The force calculation method for the combined structure of soil nailing walls between piles on a slope comprises the following steps: S100: analyzing the shape and size of horizontal soil arches between piles; S200: calculating the load of anti-sliding piles; S300: calculating the load of soil nailing walls; and S400: dividing the soil nail anchoring section and the free section according to the load of the soil nailing walls. The force calculation method for the combined structure of soil nailing walls between piles on a slope takes into account the influence of the soil arch effect on the force of the soil nailing walls 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-sliding piles + soil nailing walls; on the other hand, it can optimize the layout of soil nails and more accurately divide the free section and the anchoring section of soil nails, thereby optimizing construction, improving construction efficiency, and reducing construction costs.

Description

Technical Field

[0001] The present invention relates to the field of slope engineering, and in particular to a force calculation method, device, equipment and storage medium for a slope pile-soil nail wall combined structure. Background Art

[0002] Anti-slip pile retaining structures are widely used in high-slope cutting projects on mountain roads. In the design of the free-facing soil in front of the arch between the cantilevered piles, soil nail walls, retaining boards or retaining walls are often used to reinforce the soil. These measures can effectively prevent further weathering of the rock and soil between the piles and prevent soil collapse.

[0003] When using soil nail walls to reinforce the free-facing surface of a cantilevered section, the horizontal soil arching effect between piles significantly impacts the loads on the soil nail wall structure and the soil nails themselves. However, current standards only provide simple regulations for soil nail spacing and length, failing to fully consider the impact of this horizontal soil arching effect on the loads of the soil nail wall structure. Designers often calculate the loads of various parts of the soil nail wall between piles and design the soil nail length based on the standards or the design firm's experience.

[0004] Therefore, in the prior art, for the combined structure of soil nail walls between slope piles, those skilled in the art did not fully consider the influence of the horizontal soil arch effect when designing, and there were large errors in the accuracy of the force on the soil nail walls between piles and the division of the free section and the anchoring 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 have not fully considered the influence of the horizontal soil arch effect on the combined structure of soil nailing walls between slope piles during design. The purpose is to provide a force calculation method, device, equipment and storage medium for the combined structure of soil nailing walls between slope piles to solve the above problem.

[0006] The present invention is achieved through the following technical solutions:

[0007] In a first aspect, the present invention provides a method for calculating the stress of a slope pile-soil nail wall composite structure, comprising the following steps:

[0008] S100: Analyze the shape and size of the horizontal soil arch between piles and determine the scope of the unstable soil area in front of the arch between piles;

[0009] S200: Calculation of soil nailing wall loads between piles based on horizontal soil arching effect;

[0010] S300: Divide the soil nail anchoring section and free section according to the shape and size of the horizontal soil arch between piles;

[0011] S400: Based on S100-S300, determine the soil nail length;

[0012] S500: After soil nailing to reinforce the unstable soil between piles and in front of the arch, the load on the anti-slip piles is calculated considering the effect of the soil between piles and in front of the arch.

[0013] In one possible design, step S100 includes the following steps:

[0014] S110: Connect two adjacent anti-slide piles and draw a horizontal soil arch;

[0015] S120: According to the cross-sectional width of the anti-slide piles and the clear distance between the piles, the center arch height, inner edge arch height, and outer edge arch height of the horizontal soil arch are obtained.

[0016] In a possible design, in step S120, the center crown height h, the inner edge crown height h1, and the outer edge crown height h2 are obtained according to the following formula:

[0017]

[0018] Where a is the width of the pile section and d is the clear distance between piles.

[0019] In one possible design, step S200 includes the following steps:

[0020] S210: Calculate the active earth pressure generated by the soil in front of the arch between piles;

[0021] S220: Calculate the residual sliding force of the soil in front of the arch between piles;

[0022] S230: Take the larger value of the two to obtain the soil nail wall load.

[0023] In one possible design, step S210 includes the following steps:

[0024] S211: Use the wedge balance method to divide the wedge and calculate the active earth pressure based on the static equilibrium condition;

[0025] S212: If the rock mass is cohesionless, the active earth pressure E is obtained according to the following formula a1 :

[0026]

[0027] Where G1 is the deadweight of the wedge TCG; G2 is the deadweight of the wedge OSG; α is the angle between the back of the retaining structure wall and the horizontal plane, which is an obtuse angle when the slope is reversed, and α>90°; β is the angle between the top of the slope and the horizontal plane; θ is the angle between the soil fracture surface and the horizontal plane; H1 is the vertical height of the slope; H2 is the length of the potential fracture surface; γ is the soil weight; is the friction angle of soil internal; δ is the friction angle of soil against the back of the wall;

[0028] S213: If the rock mass is clay, the active earth pressure E is obtained according to the following formulaa2 :

[0029]

[0030] Wherein, L1 is the length of the bottom surface of the potential fracture surface; L2 is the length of the vertical surface of the potential fracture surface; c is the cohesion of the soil; for other parameters, refer to step S212.

[0031] In one possible design, in step S212, when the slope is soft rock or weathered and broken rock, the active earth pressure is obtained by substituting the comprehensive internal friction angle into the active earth pressure calculation formula:

[0032] Comprehensive internal friction angle Among them, θ R is the angle between the rock mass fracture surface and the horizontal direction; γ R is the rock mass; c R is the cohesion of the rock mass; is the friction angle within the rock mass.

[0033] In one possible design, step S300 includes the following steps:

[0034] S310: Calculate the slope rupture angle, and obtain the position of the bottom surface of the potential rupture surface through the slope rupture angle;

[0035] S320: If the soil nail intersects the arch axis of the horizontal soil arch, establish a coordinate system and divide the soil nail anchoring section and the free section using the following formula:

[0036]

[0037] Among them, 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; θ i is the angle between the soil nail and the horizontal plane; α i is the angle between the shotcrete surface and the vertical direction; l is the distance from the pile top line to the top of the shotcrete surface; z is the height of the soil nail from the top of the soil nail wall; h0 is the vertical height or length of the vertical surface formed by the axis of the horizontal soil arch above the fracture surface; x is the distance from the soil nail to the mid-span section between the piles;

[0038] S330: If the soil nail does not intersect the arch axis of the horizontal soil arch, the soil nail anchoring section and the free section are divided according to the strip division method.

[0039] In one possible design, in S400, the soil nail length is calculated based on the following formula:

[0040] L=L f +L α ;

[0041] Where L is the length of soil nail, L f is the free length of soil nail, La is the length of the soil nail anchoring section.

[0042] In one possible design, S500 includes the following steps:

[0043] S510: Obtaining strips and blocks according to the transfer coefficient method;

[0044] S520: According to the calculation formula Obtain anti-slide pile load;

[0045] Among them, E is the actual load of the anti-sliding pile considering the effect of the soil between piles, a is the width of the pile section, d is the clear distance between piles, and E n-1 is the residual sliding force at the strips and blocks on the pile back; E n It is the residual sliding force in the strips between piles.

[0046] In a possible design, when the inter-pile block is a lower slider, E n-1 >E n When the bar between piles is an anti-sliding block, E n-1 <E n .

[0047] In a second aspect, the present invention provides a force calculation device for a soil nail wall composite structure, comprising:

[0048] Acquisition unit: Analyze the shape and size of the horizontal soil arch between piles and determine the scope of the unstable soil area in front of the arch between piles;

[0049] Soil nail wall load calculation unit: calculation of soil nail wall load between piles based on horizontal soil arching effect;

[0050] Soil nail division unit: The soil nail anchoring section and free section are divided according to the shape and size of the horizontal soil arch between piles;

[0051] Soil nail length calculation unit: determine the soil nail length;

[0052] Anti-slide pile load calculation unit: After soil nailing is used to reinforce the soil between the piles and in the unstable area in front of the arch, the load on the anti-slide piles is calculated considering the effect of the soil between the piles and in front of the arch.

[0053] In a third aspect, the present invention provides a device for executing the aforementioned method for calculating the stress of a slope pile-soil nail wall composite structure.

[0054] In a fourth aspect, the present invention provides a storage medium having instructions stored thereon. When the instructions are run on a computer, the computer executes the force calculation method for the slope pile-soil nail wall composite structure.

[0055] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0056] 1. The force calculation method for the combined structure of soil nailing walls between piles takes into account the influence of soil arching on the force of the combined structure of soil nailing walls between piles. This method not only explains the influence of soil arching on the force distribution of the combined structure of anti-slide piles and soil nailing walls, but also optimizes the layout of soil nails and more accurately divides the free and anchored sections of soil nails, thereby optimizing construction, improving construction efficiency, and reducing construction costs.

[0057] 2. The force calculation method for the combined structure of soil nailing walls between piles on the slope is based on theoretical analysis and provides relevant calculation formulas, which facilitates relevant calculations by staff and can estimate the design value of the active earth pressure of the soil nailing walls between piles, making it easy to apply.

[0058] 3. It can be applied to hard plastic or hard clay soil, cemented or weakly cemented silt, sand, gravel, soft rock and weathered broken rock layer, etc. It is easy to form soil arch between piles and is suitable for road cutting slope reinforcement with soil nailing. It has a wide range of use and good practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. In the drawings:

[0060] Figure 1 It is a schematic plan view of the soil arching effect between piles and the stress analysis of the soil nail wall structure.

[0061] Figure 2 This is a schematic diagram of the overhead structure of the soil nail wall combined structure between slope piles.

[0062] Figure 3 for Figure 2 Schematic cross-section diagram.

[0063] Figure 4 Schematic diagram of the load on the soil nailing wall between piles when considering the horizontal soil arch effect.

[0064] Figure 5 When the rock mass is cohesionless soil, Figure 4 Schematic diagram of the load on the soil wedge behind the wall.

[0065] Figure 6 When the rock mass is clay, Figure 4 Schematic diagram of the load on the soil wedge behind the wall.

[0066] Figure 7 Schematic diagram of the segmented soil nailing between piles.

[0067] Figure 8The figure is a flow chart of a stress calculation method for a slope pile-soil nail wall composite structure.

[0068] Figure 9 Schematic diagram of the structure of the simulated slope in Example 2.

[0069] Figure 10 Schematic diagram of the calculation of earth pressure of the soil nail wall between piles in Example 2.

[0070] Figure 11 This is a simplified diagram of the soil nail wall design calculation in Example 2. DETAILED DESCRIPTION

[0071] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0072] In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that these specific details are not necessarily required to practice the present invention. In other embodiments, well-known structures, circuits, materials, or methods are not described in detail to avoid obscuring the present invention.

[0073] Throughout this specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Therefore, appearances of the phrases "one embodiment," "an embodiment," "an example," or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combinations and / or subcombinations. Furthermore, it will be understood by those of ordinary skill in the art that the figures provided herein are for illustrative purposes only and are not necessarily drawn to scale. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0074] In the description of the present invention, the terms "front", "back", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the scope of protection of the present invention.

[0075] Example 1:

[0076] According to existing research, the soil arch effect between piles is closely related to the stability of the soil between piles. Only when the distance between piles meets a certain range can the pile-soil interaction be effectively exerted to form the soil arch effect. At the same time, in the existing technology, those skilled in the art have generally believed that the soil arch is a compacted arch body that is in an elastic state relative to the surrounding soil through model tests and numerical simulation analysis of the formation mechanism. Specifically, see Figure 1 From the outside to the inside, the soil between the piles is distributed in the unstable area, the compacted area and the stable area in sequence. Among them, the compacted area is arched, that is, the soil arch; the soil between the piles is divided into the soil in front of the arch in the unstable area, the compacted arch in the soil arch and the soil behind the arch in the stable area.

[0077] Further explanation is given in conjunction with the soil nailing wall operation between piles: anti-slip pile construction; layered excavation of the soil in front of the piles to set up soil nails and soil nail walls.

[0078] After the soil in front of the piles is excavated, the unloaded soil between the piles can cause external compression and collapse in unstable areas. Anti-slide piles have been constructed and provide supporting arches. Due to the presence of these arches, the soil behind the piles will experience uneven or relative displacement under the action of the landslide thrust. When the soil has reached a certain shear strength, the soil particles will exert a wedge-tightening effect, forming a compacted area behind the piles and a soil arch. Once the soil arch is formed, the soil behind it will be stable. Simultaneously, during the layered excavation of the soil in front of the piles, increasing landslide thrust or earth pressure is continuously generated. At this time, the soil arch is gradually compacted and formed from top to bottom, transmitting the slope soil pressure or landslide thrust to the pile body.

[0079] For the unstable area, soil nails are used to reinforce the soil in front of the arch in the unstable area, and tightly connect it with the compacted arch 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 behind the pile and the soil behind the arch play the role of the soil nail anchoring section.

[0080] According to the specification "TB10025-2019 Railway Roadbed Support Structure Design Code", anti-slide piles are designed as bending members, and the total horizontal displacement of the pile top should be less than 1 / 100 of the cantilever length (anti-slide pile) and should not be greater than 100mm. Based on this, it can be seen that in actual slope reinforcement projects, anti-slide piles can produce bending deformation or rotation that is allowed by the specification. Figure 1 As shown in the figure, since the soil arch is a compacted elastic arch, when the pile body supporting the arch foot produces a certain amount of deformation, it will push the stable soil in front of the arch reinforced by soil nails between the piles. At this time, the soil in front of the arch will play an anti-slip role to share the total residual sliding force of the slope.

[0081] Based on the aforementioned pile-soil interaction and soil arch formation mechanism, this embodiment proposes a method for calculating the stress of a combined structure of soil nailing walls between piles on a slope. The method takes into account the influence of the soil arching effect on the stress of the combined structure of soil nailing walls between piles. On the one hand, it can explain the influence of soil arching on the stress distribution of the combined structure of anti-sliding piles and soil nailing walls. On the other hand, it can also optimize the layout of soil nails and more accurately divide the free section and anchor section of soil nails, thereby optimizing construction, improving construction efficiency, and reducing construction costs.

[0082] like Figure 8 As shown, the present invention provides a method for calculating the stress of a slope pile-soil nail wall composite structure, comprising the following steps:

[0083] S100: Analyze the shape and size of the horizontal soil arch between piles and determine the scope of the unstable soil area in front of the arch between piles;

[0084] S200: Calculation of soil nailing wall loads between piles based on horizontal soil arching effect;

[0085] S300: Divide the soil nail anchoring section and free section according to the shape and size of the horizontal soil arch between piles;

[0086] S400: Based on S100-S300, determine the soil nail length;

[0087] S500: After soil nailing to reinforce the unstable soil between piles and in front of the arch, the load on the anti-slip piles is calculated considering the effect of the soil between piles and in front of the arch.

[0088] In the force calculation method for the slope pile-soil nail wall composite structure, for step S100, the pile spacing between two adjacent anti-slide piles is used as a basis to obtain the shape and size of the corresponding soil arch, thereby facilitating the division of the area where the soil between the piles is located and providing a basis for subsequent calculations.

[0089] The forces acting on the soil between the piles are borne separately by the anti-slide piles and the soil nail wall. The specific force distribution is calculated in steps S200 and S500, respectively. This not only provides the force values for both, but also facilitates comparison of force distribution. Furthermore, based on step S200, the lengths of the anchor and free segments of the soil nails are divided according to the load on the soil nail wall to optimize the placement of the soil nails. The length of the soil nails can then be determined based on the lengths of the anchor and free segments.

[0090] Specifically, for step S100, current design standards and research results all assume that the horizontal soil arch is symmetrical about the mid-span section. Without considering the shape change of the soil arch along the pile length, it can be simplified to a plane problem. Step S100 then includes the following steps:

[0091] S110: Connect two adjacent anti-slide piles and draw a horizontal soil arch;

[0092] S120: According to the cross-sectional width of the anti-slide piles and the clear distance between the piles, the center arch height, inner edge arch height, and outer edge arch height of the horizontal soil arch are obtained.

[0093] Among them, for the shape of the soil arch, according to the Chongqing local standard "Geological Hazard Prevention Engineering Design Standard" (DBJ50 / T-029-2019), if Figure 2 As shown in the figure, the soil arch is set as an isosceles right triangle when viewed from above. Figure 2 In, F max The maximum value of landslide thrust is the maximum value among natural conditions, rainstorm conditions and earthquake conditions.

[0094] For step S110, Figure 2 As shown in the figure, let two adjacent anti-slip piles be piles Z1 and Z2. Pile Z1's back has an axis O1, inner edge A1, and outer edge B1, while pile Z2's back has an axis O2, inner edge A2, and outer edge B2. Therefore, a horizontal soil arch A1AA2O2B2BB1O1A1 is formed between piles Z1 and Z2. The center height of the horizontal soil arch is defined as axis O, inner edge A, and outer edge B. Therefore, A1AA2 is the inner edge of the arch, O1OO2 is the arch axis, and B1BB2 is the outer edge of the arch.

[0095] Based on the "Design Standard for Geological Hazard Prevention and Control Engineering" (DBJ50 / T-029-2019), A1AA2 and B1BB2 are both isosceles right triangles.

[0096] Next, let the sprayed anchor surface be M1, the midpoint of the sprayed anchor surface be C, and the projection of point C on the line A1A2 at the pile location be D. Point D is also the midpoint of the line A1A2 at the pile location. Then, let CD be the distance between the sprayed anchor surface and the line A1A2 at the pile location, and let its length be l. Furthermore, let the cross-sectional width of the (anti-slip) pile be a, the height be b, and the clear distance between piles be d. Based on this, step S130 is performed to obtain the center arch height, inner edge arch height, and outer edge arch height of the horizontal soil arch.

[0097] Preferably, in step S120, the center crown height h, the inner edge crown height h1 and the outer edge crown height h2 are obtained according to the following formula:

[0098]

[0099] Where a is the width of the pile section and d is the clear distance between piles.

[0100] exist Figure 2 Make its cross-section diagram based on Figure 3, where the soil has a potential sliding surface. Let the intersection of the potential sliding surface and the shotcrete surface be T, the intersection with the anti-sliding pile be F, the intersection with the soil arch axis be O', the intersection of the potential sliding surface be K, the vertex of the shotcrete surface be C, the vertex of the anti-sliding pile back be D, and the vertex of the soil arch axis be O.

[0101] The vertex C of the shotcrete surface, the vertex D of the anti-slide pile back and the vertex O of the soil arch axis correspond to Figure 2 The midpoint C of the shotcrete surface, the projection point D of the line A1A2 at the pile location, and the center arch height axis O of the horizontal soil arch are represented by the same symbol.

[0102] Based on this, the central arch height h of the soil arch, that is, the arch axis, corresponds to Figure 3 At the same time, Figure 3 As shown, the inner edge arch height h1 is located on the left side of OO', and the outer edge arch height h2 is located on the right side of OO'.

[0103] In step S200, when considering the horizontal soil arching effect, the force acting on the soil nail wall is the active earth pressure or the residual sliding force generated by the soil in front of the arch between the piles, whichever is greater. Therefore, the active earth pressure and the residual sliding force generated by the soil in front of the arch between the piles must be calculated separately. In other words, step S200 includes the following steps:

[0104] S210: Calculate the active earth pressure generated by the soil in front of the arch between piles;

[0105] S220: Calculate the residual sliding force of the soil in front of the arch between piles

[0106] S230: Take the larger value of the two to obtain the soil nail wall load.

[0107] Specifically, for step S210, the active earth pressure generated by the soil in front of the pile arch can be calculated according to the classical Coulomb earth pressure theory. When the soil arch effect is not considered, the load on the soil nail wall can be directly calculated according to the specification "JTGD30-2015 Highway Roadbed Design Specification". However, when the soil arch effect is considered, the wedge balance method is used for calculation; Figure 4 As shown in the figure, the soil has a potential sliding surface and a soil rupture surface. Let the intersection of the potential sliding surface and the shotcrete surface be T, the intersection with the anti-sliding pile be F, the intersection with the soil arch axis be O', and the vertex of the potential sliding surface be K; the potential rupture surface is inclined, its lower end surface intersects with point T, and its upper end intersects with the soil at G; the vertex of the shotcrete surface is C, the vertex of the soil arch axis is O, and the intersection of the soil arch axis and the potential rupture surface is S. O1 and O1' are the two end points of the hypothetical soil arch axis O1O1', and the soil arch axis O1O1' does not intersect with the soil rupture surface TG.

[0108] in, Figure 3 and Figure 4In the figure, some endpoints, such as the intersection points of the potential sliding surface and each structure, correspond to each other and are therefore represented by the same symbols.

[0109] Assuming the soil nail wall surface (i.e., the aforementioned shotcrete surface) is rigid, when the wall CT slides or rotates about its toe, it causes the soil wedge CTG behind the wall to fail. Specifically, it slides downward along the wall back CT and through the potential failure surface TG. At the moment of failure, the wedge CTG is in a state of limit equilibrium. Using the static equilibrium condition, the active earth pressure on the soil nail wall surface can be solved.

[0110] Based on this, when considering the soil arching effect, assuming that the arch axis OO' intersects the soil rupture surface TG at point S, the active earth pressure on the soil nail wall is generated by the strip CTSO. In this case, step S310 only needs to calculate the active earth pressure of the strip CTSO.

[0111] Specifically, step S210 includes the following steps:

[0112] S211: Use the wedge balance method to divide the wedge and calculate the active earth pressure based on the static equilibrium condition;

[0113] S212: If the rock mass is cohesionless, the active earth pressure E is obtained according to the following formula a1 :

[0114]

[0115] Where G1 is the deadweight of the wedge TCG; G2 is the deadweight of the wedge OSG; α is the angle between the back of the retaining structure wall and the horizontal plane, which is an obtuse angle when the slope is reversed, and α>90°; β is the angle between the top of the slope and the horizontal plane; θ is the angle between the soil fracture surface and the horizontal plane; H1 is the vertical height of the slope; H2 is the length of the potential fracture surface; γ is the soil weight; is the friction angle of soil internal; δ is the friction angle of soil against the back of the wall;

[0116] S213: If the rock mass is clay, the active earth pressure E is obtained according to the following formula a2 :

[0117]

[0118] Wherein, L1 is the length of the bottom surface of the potential fracture surface; L2 is the length of the vertical surface of the potential fracture surface; c is the soil cohesion; for other parameters, refer to step S212.

[0119] Based on this, for weakly cemented sandy soil, crushed gravel soil and other cohesive soils, for hard plastic or hard clay soil, cemented or weakly cemented silt soil and other cohesive soils, the stress conditions of the soil wedge are different due to the different cohesiveness of the soil. For details, see Figure 5 and Figure 6, so they are calculated separately to obtain more accurate results.

[0120] in, Figure 5 Where Ψ1 is the angle between the active earth pressure direction of the cohesionless soil behind the wall and the vertical plane; δ1 is the friction angle of the cohesionless soil on the wall back; is the internal friction angle of cohesionless soil; θ1 is the rupture angle of the cohesionless soil slope.

[0121] Figure 6 Where Ψ2 is the angle between the active earth pressure direction of the clay behind the wall and the vertical plane; δ2 is the friction angle of the clay on the wall; is the internal friction angle of clay soil; θ2 is the rupture angle of clay soil slope.

[0122] In one possible implementation, in step S212, when the slope is soft rock or weathered and broken rock, the active earth pressure is obtained by substituting the comprehensive internal friction angle into the active earth pressure calculation formula:

[0123] Comprehensive internal friction angle Among them, θ R is the angle between the rock mass fracture surface and the horizontal direction; γ R is the rock mass; c R is the cohesion of the rock mass; is the friction angle within the rock mass.

[0124] Based on this, according to engineering experience, the active earth pressure is calculated by integrating the internal friction angle to simplify the calculation and calculate the active earth pressure quickly and accurately.

[0125] For step S220, Figure 4 As shown in the figure, when considering the soil arching effect, the residual sliding force on the soil nailing wall between piles is generated by the soil within the potential sliding surface. Due to the soil arching between the piles, the landslide thrust behind the arch is transmitted to the anti-slide piles through the arch body and arch foot. At this time, the soil nailing wall between piles only bears the residual sliding force of the soil before the arch, that is, the residual sliding force generated by the strip OCTO'. The magnitude of this residual sliding force can be calculated using the strip method.

[0126] Based on this, the active earth pressure and the residual sliding force generated by the soil in front of the arch between the piles are calculated through steps S210 and S220 respectively, and the larger one is taken to complete step S230.

[0127] Regarding step S300, step S300 includes the following steps:

[0128] S310: Calculate the slope rupture angle, and obtain the position of the bottom surface of the potential rupture surface through the slope rupture angle;

[0129] S320: If the soil nail intersects the arch axis of the horizontal soil arch, establish a coordinate system and divide the soil nail anchoring section and the free section using the following formula:

[0130]

[0131] Among them, 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; θ i is the angle between the soil nail and the horizontal plane; α i is the angle between the shotcrete surface and the vertical direction; l is the distance from the pile top line to the top of the shotcrete surface; z is the height of the soil nail from the top of the soil nail wall; h0 is the vertical height or length of the vertical surface formed by the axis of the horizontal soil arch above the fracture surface; x is the distance from the soil nail to the mid-span section between the piles;

[0132] S330: If the soil nail does not intersect the arch axis of the horizontal soil arch, the soil nail anchoring section and the free section are divided according to the strip division method.

[0133] Among them, in step S310, if Figure 4 As shown in Figure 1, when considering horizontal soil arching and soil nailing to reinforce the soil in front of the arch, the potential failure surface OST is a broken line. The OS segment is located on the central arch axis of the soil arch, and the ST segment is located on the soil failure surface when soil arching between piles is not considered. The location of the ST segment can be determined by calculating the slope failure angle θ according to existing standards.

[0134] Specifically, for the OS segment, such as Figure 7 As shown in the figure, if the soil nails are first arranged to intersect with the axis of the soil arch, then the line connecting the top of the pile back A1A2 (i.e. Figure 2 The coordinate system is established with the midpoint D of the line A1A2 at the stake as the origin. The directions of the X-axis, Y-axis and Z-axis are as follows: Figure 7 As shown, the Z-axis direction is vertically downward.

[0135] Assume that the soil nail MN intersects the CT section at point M1, and the soil nail MN intersects the soil arch axis at point N1. The coordinates of point M1 are (x, y, z). For safety reasons, the center 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 Point N1 in the middle. Let the angle between the soil nail and the horizontal plane be θ i , the angle between the spray anchor surface and the vertical direction is α i , the distance from the line connecting the pile top A1A2 to the top line of the sprayed anchor surface is l. Assume that the total length of the soil nail MN is L, and the soil nail consists of a free section MN1 and an anchoring section N1N, with lengths L and L respectively. f 、L a , that is, L=L f +L a .

[0136] After obtaining the location of the potential fracture surface (ODB) in step S310, soil nails can be divided into two categories: those intersecting the BD segment of the ODB and those intersecting the OD segment of the ODB. For the former, the soil nail anchoring segment is divided into a free segment in step S320, while for the latter, the soil nail anchoring segment is divided into a free segment in step S330. Specifically, calculations can be performed according to the relevant provisions of the "TB10025-2019 Code for Design of Railway Roadbed Support Structures."

[0137] In step S400, the soil nail length is calculated based on the following formula:

[0138] L=L f +L α ;

[0139] Where L is the length of soil nail, L f is the free length of soil nail, L a is the length of the soil nail anchoring section.

[0140] 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.

[0141] For step S500, the existing specification adopts the transfer coefficient method (strip method) for calculation. The calculated load borne by a single anti-slide pile is the residual sliding force or soil pressure within the range of the center distance of the anti-slide pile on the left and right sides. Figure 2 For example, pile Z2 bears all sliding loads within the CC' range. Analysis of the pile-soil interaction and the soil arch formation mechanism shows that because the soil arch is a compacted elastic arch, when the pile body, which supports the arch foot, experiences a certain amount of deformation, it pushes against the stable soil in front of the arch, which has been reinforced by soil nails. At this time, the soil in front of the arch will play an anti-sliding role, sharing the total residual sliding force of the slope.

[0142] In other words, if Figure 2 As shown in the figure, after the soil nail wall is set between the piles, all the sliding loads within the range of O1O2 (including the AA1A2 area in front of the arch between the piles) are shared by the two anti-sliding piles on the left and right (pile Z1 and pile Z2).

[0143] Based on this, step S500 includes the following steps:

[0144] S510: Obtaining strips and blocks according to the transfer coefficient method;

[0145] S520: According to the calculation formula Obtain anti-slide pile load;

[0146] Among them, E is the actual load of the anti-sliding pile considering the effect of the soil between piles, a is the width of the pile section, d is the clear distance between piles, and E n-1is the residual sliding force at the strips and blocks on the pile back; E n It is the residual sliding force in the strips between piles.

[0147] Combine Figure 3 , E n For the strips between piles, that is Figure 3 The TCDF of the bars in E n-1 It is a strip at the back of the pile, that is Figure 3 The bar DFOO' in the . n and E n-1 The calculations are done using the strip method, which will not be described here. Figure 3 As shown in the figure, a small amount of soil nails pass through the potential sliding surface BO1'. For safety reasons, the influence of the anchoring force of this part can be ignored when calculating the anti-sliding pile force.

[0148] It is worth noting that: when the bar between piles is a lower sliding block, E n-1 >E n When the bar between piles is an anti-sliding block, E n-1 <E n Based on this, Figure 3 As shown in the figure, after the soil nails are set, the soil nails anchor the strip TCDF, strip DFOO' and the soil behind the arch into a whole. Therefore, the actual force E of the anti-sliding pile needs to take into account the sliding characteristics of the strip TCDF between the piles, that is, when the strip TCDF is the sliding block, E n-1 >E n When the strip TCDF is an anti-sliding block, E n-1 <E n .

[0149] 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 strip method to calculate E n and E n-1 , and finally substituted into the calculation formula to obtain the actual force E on the anti-slip pile. In engineering applications, most inter-pile strips serve as anti-slip elements. Therefore, using soil nail walls or external panels to reinforce the rock and soil between piles not only helps reduce the amount of excavation, but also reduces the force on the anti-slip pile body and optimizes the combined structural force.

[0150] Example 2:

[0151] This embodiment provides a hardware device for implementing the force calculation method of the slope pile-soil nail wall composite structure described in Example 1, including:

[0152] Acquisition unit: Analyze the shape and size of the horizontal soil arch between piles and determine the scope of the unstable soil area in front of the arch between piles;

[0153] Soil nail wall load calculation unit: calculation of soil nail wall load between piles based on horizontal soil arching effect;

[0154] Soil nail division unit: The soil nail anchoring section and free section are divided according to the shape and size of the horizontal soil arch between piles;

[0155] Soil nail length calculation unit: determine the soil nail length;

[0156] Anti-slide pile load calculation unit: After soil nailing is used to reinforce the soil between the piles and in the unstable area in front of the arch, the load on the anti-slide piles is calculated considering the effect of the soil between the piles and in front of the arch.

[0157] The working process, working details and technical effects of the device provided in this embodiment can be found in Example 1 and will not be described in detail here.

[0158] This embodiment provides a device for executing the aforementioned method for calculating the stress of a slope pile-soil nail wall composite structure. The working process, working details, and technical effects of the device provided in this embodiment can be found in Example 1 and will not be described in detail here.

[0159] This embodiment provides a storage medium storing instructions that, when executed on a computer, execute the method for calculating the stress of a slope pile-soil nail wall composite structure. The storage medium refers to a data storage medium and may include, but is not limited to, a floppy disk, a CD, a hard disk, a flash memory, a USB flash drive, and / or a memory stick. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable device.

[0160] This embodiment provides a computer program product that, when executed on a computer, causes the computer to execute the aforementioned method for calculating the stress of a slope pile-soil nail wall composite structure. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device.

[0161] Example 3:

[0162] Based on Example 1, an engineering practice is simulated to illustrate how the force calculation method for the slope pile-soil nail wall composite structure is actually applied:

[0163] Assuming the slope is a mid-hill topography, the surface cover is the Quaternary Holocene slope floodplain. The gravelly clay has a maximum thickness of 12m and is hard plastic. The underlying bedrock is the Xintiangou Formation of the Middle Jurassic (J 2x ) mudstone and sandstone; the physical and mechanical parameters of the slope rock and soil are shown in Table 1. Because a road is paved on the top of the cutting slope in this section, the slope is limited. The design uses a combined structure of pile-to-pile soil nailing and wall reinforcement, with anti-slip piles installed at the slope foot and soil nailing walls arranged between the piles.

[0164]

[0165] Table 1 Physical and mechanical parameters of slope rock and soil

[0166] In this slope reinforcement project, the proposed pile cross-section is 2m×2.5m, the pile spacing is 6m, and the pile length is 18 meters, of which the cantilever section and anchor section are both 9m, and the soil excavation slope ratio between piles is 1:0.2. According to the calculation in step S130 of the force calculation method for the combined structure of soil nailing wall between piles, the horizontal soil arch height at the center section between piles is 3m. And if Figure 9 As shown, for the convenience of calculation, a dividing line is set at the arch axis and the pile location to divide the potential sliding body into strips and blocks.

[0167] According to step S200 of the force calculation method for the combined structure of soil nailing wall between piles, the anti-slide pile load calculation is performed. Considering the engineering safety, according to the requirements of the "Highway Roadbed Design Code" and the actual situation of the slope, the safety factor K = 1.2 (rainstorm condition) is taken. Figure 9 After the strips are divided as shown, the residual sliding force of the excavation slope is calculated according to step S220. The results are shown in Table 2. The residual sliding force at the wall (strip 11) is 383.2 kN / m, and the residual sliding force at the pile (strip 10) is 475.6 kN / m.

[0168]

[0169] Table 2 Calculation table of residual sliding force of single width section

[0170] Among them, in Table 2, T i =W i k0sinα i , E i =ψ i E i-1 +T i -R i .

[0171] It can be seen that in this engineering example, the arch front blocks 9, 10, and 11 between the piles all play an anti-sliding role. Therefore, the load on the anti-sliding pile considering the effect of the soil between the piles is calculated as follows according to step S220:

[0172]

[0173] The soil nail wall load calculation is performed according to step S300 of the force calculation method for the combined structure of soil nail wall between piles. In this example, the angle between the wall panel and the vertical plane is 11°, the height of the horizontal soil arch in the mid-span between piles is 3m, and the earth pressure calculation diagram of the soil nail wall between piles is as follows: Figure 10 According to the formula provided in step S300, the friction angle between the soil and the panel is δ = 16.67°, the crack angle of the soil behind the wall is θ = 46°, and the other calculation parameters are as follows: Figure 10and as shown in Table 1.

[0174] When considering soil arching effect, Figure 10 The active earth pressure of the sliding wedge CUOST on the wall panel is solved by the middle fracture surface TSO. The result is E a1 =142.38kN / m. Due to the soil arch effect, the force of the strips behind the arch is ignored. Figure 9 The residual sliding force of the arch front strips (9-11) between piles on the wall panel is solved for the potential sliding surface shown in Table 3. The result is T 11 =0kN / m. Taking the larger of the two, the load on the wall panel when considering the soil arching effect should be the soil pressure, which is 142.38kN / m.

[0175]

[0176] Table 3 Calculation table of residual sliding force on the soil nail wall in front of the single-width section of the soil in front of the arch

[0177] The soil nailing wall is designed according to step S400 of the force calculation method for the combined structure of soil nailing wall between slope piles, wherein: Figure 11 As shown, the soil nail spacing is 1.0m×1.3m, with 6 rows and 5 columns in total, and the angle between the soil nails and the horizontal plane is 10°. HRB400 threaded steel bars, poured with M30 cement mortar, the surface layer adopts two layers @ The thickness of steel mesh and sprayed C30 concrete is 20cm; the outer steel mesh frame steel bars are Round steel.

[0178] When considering the soil arching effect, the soil nail wall load is 142.38 kN / m, and the free and anchor sections of the soil nails are calculated according to step S410. When not considering the soil arching effect, the soil nail wall load is 194.39 kN / m, and the free and anchor sections of the soil nails are calculated according to step S420. Designs were performed for these two cases, and the calculation results are listed in Table 4 for comparison.

[0179]

[0180] Table 4 Comparison of calculation results of soil nail wall design Based on the above calculations and the results summarized in Table 5, the details are as follows:

[0181]

[0182] Table 5 Calculation results of the example

[0183] When the soil effect between piles is not considered and when the soil effect between piles is considered, the load difference rate on the anti-slide piles reaches 14.57%; the soil nail wall between piles is greatly affected by the horizontal soil arch effect, and the load difference rate on the wall in the mid-span section alone reaches 26.75%. The corresponding nail material saving when the horizontal soil arch effect is considered reaches 15.68.

[0184] This shows that considering the horizontal soil arching effect between piles and the soil in front of the arch after soil nailing is more conducive to improving the economic efficiency of anti-slide pile design compared to traditional methods. According to the calculation method provided in Example 1, when considering the horizontal soil arching effect in soil nailing wall design, the corresponding section arch height is 1.5m. 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 soil nail rows intersecting the arch axis will also increase. Due to space limitations, calculations are not performed for all sections. The entire soil nailing wall design can be completed according to the calculation method provided in Example 1.

[0185] In summary, considering the influence of horizontal soil arch effect between piles, when laying out soil nails between piles, differentiated layout can be carried out according to the shape and size of the soil arch. Soil nails can be appropriately increased and lengthened in the high arch part of the mid-span to further optimize the design and improve the economy of the soil nail wall design between piles.

[0186] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. The force calculation method of the combined structure of soil nailing wall between slope piles is characterized by: The following steps are involved: S100: Analyze the shape and size of the horizontal soil arch between piles and determine the scope of the unstable soil area in front of the arch between piles; S200: Calculation of soil nailing wall loads between piles based on horizontal soil arching effect; S300: Divide the soil nail anchoring section and free section according to the shape and size of the horizontal soil arch between piles; S400: Based on S100-S300, determine the soil nail length; S500: After soil nailing to reinforce the unstable soil between piles and in front of the arch, the load on the anti-slip piles is calculated considering the effect of the soil between piles and in front of the arch. Step S200 includes the following steps: S210: Calculate the active earth pressure generated by the soil in front of the arch between piles; S220: Calculate the residual sliding force of the soil in front of the arch between piles; S230: Take the larger value of the two to obtain the soil nail wall load; Step S210 includes the following steps: S211: Use the wedge balance method to divide the wedge and calculate the active earth pressure based on the static equilibrium condition; S212: If the rock mass is cohesionless, the active earth pressure is obtained according to the following formula E a1 : ； ； ； in, G 1 Wedge TCG self-respect; G 2 Wedge OSG The deadweight of T For the wall CT Soil fracture surface TG The intersection, endpoint C For the wall CT With slope CG The intersection, endpoint G Soil fracture surface TG With slope CG The intersection of TCG Middle earth arch axis OO' And delineate potential rupture surfaces, endpoints O The potential fracture surface and the slope surface CG The intersection, endpoint S The potential fracture surface and the soil fracture surface TG The intersection of α It is the angle between the back of the retaining structure wall and the horizontal plane. When it is tilted backward, it is an obtuse angle. α >90°; β is the angle between the top of the slope and the horizontal plane; θ is the angle between the soil fracture 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 It is the 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 mass is clay, the active earth pressure is obtained according to the following formula E a2 : ； in, 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 other parameters, refer to step S212; In step S212, when the slope is soft rock or weathered and broken 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 ,in, θ R is the angle between the rock mass fracture surface and the horizontal direction; γ R is the rock mass; c R is the cohesion of the rock mass; φ R is the friction angle within the rock mass.

2. The force calculation method for the slope pile soil nail wall composite structure according to claim 1 is characterized in that: Step S100 includes the following steps: S110: Connect two adjacent anti-slide piles and draw a horizontal soil arch; S120: According to the cross-sectional width of the anti-slide piles and the clear distance between the piles, the center arch height, inner edge arch height, and outer edge arch height of the horizontal soil arch are obtained.

3. The force calculation method for the slope pile soil nail wall composite structure according to claim 2 is characterized in that: In step S120, the center arch height is obtained according to the following formula: h , inner edge arch height h 1 and outer edge arch height h 2: ； in, a is the pile section width, d The net distance between piles.

4. The force calculation method for the slope pile soil nail wall composite structure according to claim 1 is 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 the arch axis of the horizontal soil arch, establish a coordinate system and divide the soil nail anchoring section and the free section using the following formula: ； in, L f is the free length of soil nail, L a is the length of the soil nail anchoring section; a is the pile section width; b is the pile section height; θ i is the angle between the soil nail and the horizontal plane; α i is the angle between the spray anchor surface and the vertical direction; l It is the distance from the pile top line to the top line of the shotcrete surface; z is the height of the soil nail from the top of the soil nail wall; h 0 It is the vertical height or length of the vertical plane formed by the axis of the horizontal soil arch above the fracture surface; x is the distance between the soil nail and the mid-span section between piles; S330: If the soil nail does not intersect the arch axis of the horizontal soil arch, the soil nail anchoring section and the free section are divided according to the strip division method.

5. The force calculation method for the slope pile soil nail wall composite structure according to claim 4 is characterized in that: In S400, the soil nail length is calculated based on the following formula: ； Where, 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.

6. The force calculation method for the slope pile soil nail wall composite structure according to claim 5 is characterized in that: S500 includes the following steps: S510: Obtaining strips and blocks according to the transfer coefficient method; S520: According to the calculation formula Obtain anti-slide pile load; in, E In order to consider the actual load of the anti-sliding pile body due to the effect of the soil between the piles, a is the pile section width, d is the net distance between piles, E n-1 is the residual sliding force at the strips and blocks on the pile back; E n It is the residual sliding force in the strips between piles.

7. The force calculation method for the slope pile soil nail wall composite structure according to claim 6 is characterized in that: When the bar between piles is a lower sliding block, E n-1 >E n When the blocks between piles are anti-sliding block, E n-1 < E n .

8. A soil nailing wall composite structure force calculation device for executing the slope pile soil nailing wall composite structure force calculation method according to any one of claims 1 to 7, characterized in that: include: Acquisition unit: Analyze the shape and size of the horizontal soil arch between piles and determine the scope of the unstable soil area in front of the arch between piles; Soil nail wall load calculation unit: calculation of soil nail wall load between piles based on horizontal soil arching effect; Soil nail division unit: The soil nail anchoring section and free section are divided according to the shape and size of the horizontal soil arch between piles; Soil nail length calculation unit: determine the soil nail length; Anti-slide pile load calculation unit: After soil nailing is used to reinforce the soil between the piles and in the unstable area in front of the arch, the load on the anti-slide piles is calculated considering the effect of the soil between the piles and in front of the arch.

9. A device, characterized in that The method for calculating the stress of a slope pile-soil nailing wall composite structure according to any one of claims 1 to 7 is implemented.

10. A storage medium, characterized in that: The storage medium stores instructions, and when the instructions are executed on a computer, the computer is caused to execute the force calculation method for a slope pile-soil nailing wall composite structure according to any one of claims 1 to 7.

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