Method and system for determining design parameters of rock-soil dual foundation pit hanging foot pile

Abstract

The present application relates to the field of geotechnical engineering, and aims to solve the problem of overlong design length of supporting piles, which results in waste of materials, construction period and energy consumption, and provides a decision-making method and system for design parameters of a stable rock-soil dual foundation pit cantilever pile. The decision-making method for design parameters of the stable rock-soil dual foundation pit cantilever pile comprises the following steps: based on the soil-rock parameters of the dual foundation pit, calculating the soil part sliding resistance, the soil part sliding force, the rock resistance and the horizontal soil friction, introducing a failure mode expansion coefficient and a soil friction deduction coefficient to calculate a failure coefficient; judging the failure mode of the soil-rock dual stratum according to the size of the failure coefficient, and under the corresponding failure mode, combining the current soil-rock parameters of the foundation pit to calculate the corresponding cantilever pile parameters when different types of cantilever piles reach static equilibrium. The present application can improve the high-quality level of the application of soil-rock dual foundation pit supporting and cantilever piles.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of geotechnical engineering, and in particular to a method and system for determining design parameters of a hanging pile in a soil-rock dual foundation pit. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute the prior art.

[0003] A hanging pile is a support pile that is not supported or simply reinforced at the lower part of the side wall of a foundation pit, the pile end is embedded in the rock mass but does not penetrate the basement, the pile end is higher than the basement, and mainly supports the upper soil.

[0004] Currently, the design parameters of the hanging pile of the soil-rock dual foundation pit are calculated by using finite element software, and there is no calculation theory for the hanging pile. Moreover, due to the economy, specialty and complexity of the finite element software, the engineering design is limited, the calculation of the hanging pile is difficult, and the calculation results cannot be applied to actual engineering.

[0005] In actual engineering, the "regarding rock as soil" calculation method is used to determine the design parameters of the hanging pile of the soil-rock dual foundation pit. However, regarding the stable rock layer as a soil layer for the design of the support structure ignores the rigid embedded constraint effect provided by the stable rock mass to the pile body and the condition that the rock has no lateral pressure under the condition of the stability of the rock mass, which leads to an excessively long design length of the support pile and causes waste of materials, construction period and energy consumption. SUMMARY

[0006] To solve the above technical problems, the present application provides a method and system for determining the design parameters of a hanging pile in a soil-rock dual foundation pit with stable rock mass, which can establish a matching mechanical model of the hanging pile for different failure modes and improve the high-quality level of the application of the soil-rock dual foundation pit support and the hanging pile.

[0007] To achieve the above purpose, the present application adopts the following technical solutions:

[0008] The first aspect of the present application provides a method for determining the design parameters of a hanging pile in a soil-rock dual foundation pit with stable rock mass.

[0009] In one or more embodiments, a method for determining the design parameters of a hanging pile in a soil-rock dual foundation pit with stable rock mass is provided, comprising:

[0010] Based on the soil-rock parameters of the dual foundation pit, the soil part sliding resistance, the soil part sliding force, the rock resistance and the horizontal soil friction are calculated.

[0011] The failure coefficient is obtained by summing the product of the soil partial sliding force, the failure mode propagation coefficient and the rock mass resistance, and the product of the soil friction deduction coefficient and the horizontal soil friction. The failure coefficient is obtained by quotienting the soil partial sliding force. The failure mode propagation coefficient and the soil friction deduction coefficient are either 0 or 1.

[0012] The failure mode of the soil-rock dual-layer stratum is determined based on the magnitude of the failure coefficient. Under the corresponding failure mode, combined with the current soil and rock parameters of the foundation pit, the corresponding parameters of the suspended piles when different types of suspended piles reach static equilibrium are calculated.

[0013] As one implementation method, when both the failure mode expansion coefficient and the failure mode expansion coefficient are 0: when the failure coefficient is greater than or equal to 1, no failure occurs or the previous stage failure occurs; when the failure coefficient is less than 1, the failure mode is circular arc or circular arc-plane failure.

[0014] As one implementation method, when the failure mode expansion coefficient is 1 and the failure mode expansion coefficient is 0: when the failure coefficient is greater than or equal to 1, the failure mode is circular arc or circular arc-plane failure; when the failure coefficient is less than 1, the failure mode is shear failure or sliding failure.

[0015] As one implementation method, when both the failure mode expansion coefficient and the failure mode expansion coefficient are 1: when the failure coefficient is greater than or equal to 1, the failure mode is shear failure; when the failure coefficient is less than 1, the failure mode is sliding failure.

[0016] As one implementation method, when the failure mode is circular arc or circular arc-plane failure, and the toe pile is a single-point anchored toe pile, its rock embedment depth is... The force equilibrium condition that needs to be satisfied is: When the suspended pile is a cantilevered suspended pile, its rock embedment depth is... The force equilibrium condition that needs to be satisfied is: Length of the suspended pile ;

[0017] in, The height of the soil mass; To calculate the distance between the cross section and the rock shoulder resistance; To calculate the distance between the cross section and the resultant earth pressure; This is the distance between the rock shoulder resistance and the pile bottom; This is the distance between the resultant earth pressure force and the bottom of the pile; This is the safety factor for embedded stability; This refers to the active earth pressure on the soil mass. The rock shoulder resistance provided for the rock shoulder.

[0018] As an implementation mode, when the failure mode is a section failure or a sliding section failure, the rock-socketed depth of the single-fulcrum anchor-lifting pile is The force balance condition to be met is: ; the rock-socketed depth of the cantilevered anchor-lifting pile is The force balance condition to be met is: ; the length of the anchor-lifting pile ;

[0019] wherein, is the rock failure height; is the soil height; is the distance between the calculation section and the rock shoulder resistance; is the distance between the calculation section and the resultant of the earth pressure; is the distance between the rock shoulder resistance and the pile bottom; is the distance between the resultant of the earth pressure and the pile bottom; is the embedded stability safety factor; is the active earth pressure of the soil part; is the rock shoulder resistance provided by the rock shoulder; is the friction on the soil-rock interface; is the length of the anchor rod to the pile top; is the distance between the rock-soil friction and the pile end in the case of the cantilevered anchor-lifting pile.

[0020] As an implementation mode, when the anchor-lifting pile meets the static force balance condition, the anchor-lifting pile is selected, and the stability of the soil-rock dual foundation pit is calculated by using the strip method according to the corresponding failure mode.

[0021] The second aspect of the present application provides a decision system for stabilizing the design parameters of the anchor-lifting pile of the soil-rock dual foundation pit of the rock mass.

[0022] In one or more embodiments, a decision system for stabilizing the design parameters of the anchor-lifting pile of the soil-rock dual foundation pit of the rock mass comprises:

[0023] A mechanical parameter calculation module is configured to calculate the soil part sliding resistance, the soil part sliding force, the rock resistance, and the horizontal soil friction based on the soil-rock parameters of the dual foundation pit.

[0024] A failure coefficient calculation module is configured to obtain the failure coefficient by dividing the sum of the product of the soil part sliding resistance, the failure mode expansion coefficient, and the rock resistance, and the product of the soil friction deduction coefficient and the horizontal soil friction, by the soil part sliding force; the values of the failure mode expansion coefficient and the soil friction deduction coefficient are 0 or 1.

[0025] The hanging foot pile parameter calculation module is used for judging the failure mode of the soil-rock dual stratum according to the size of the failure coefficient, and calculating the corresponding hanging foot pile parameters of different types of hanging foot piles reaching static balance under the corresponding failure mode in combination with the current soil-rock parameters of the foundation pit.

[0026] The third aspect of the present application provides a computer readable storage medium.

[0027] A computer readable storage medium having a computer program stored thereon, the program being executed by a processor to implement the steps in the decision-making method for the design parameters of the hanging foot pile of the stable rock-soil dual foundation pit as described above.

[0028] The fourth aspect of the present application provides an electronic device.

[0029] An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, the processor implementing the steps in the decision-making method for the design parameters of the hanging foot pile of the stable rock-soil dual foundation pit as described above when executing the program.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] The present application introduces a failure mode expansion coefficient and a soil friction force deduction coefficient to calculate a failure coefficient on the basis of calculating the partial anti-sliding force of the soil, the partial sliding force of the soil, the rock resistance, and the horizontal soil friction, uses the size of the failure coefficient to judge the failure mode of the soil-rock dual stratum, considers the rigid embedded constraint effect provided by the rock mass to the pile body and the condition that the rock has no lateral pressure under the stable rock mass, and then calculates the corresponding hanging foot pile parameters of different types of hanging foot piles reaching static balance under the corresponding failure mode in combination with the current soil-rock parameters of the foundation pit, thereby avoiding the waste of materials, construction period, and energy consumption caused by the overlong design length of the supporting pile, improving the high-quality level of the soil-rock dual foundation pit supporting and the application of the hanging foot pile, and providing a reference for the scientific utilization of the rock mass structure. BRIEF DESCRIPTION OF DRAWINGS

[0032] The drawings accompanying the specification of the present application serve to provide a further understanding of the present application, and the illustrative embodiments of the present application and their descriptions serve to explain the present application, and do not constitute an improper limitation on the present application.

[0033] Figure 1 is a decision-making method flow chart for the design parameters of the hanging foot pile of the stable rock-soil dual foundation pit of the embodiments of the present application;

[0034] Figure 2 is a calculation model under the circular arc failure mode of the embodiments of the present application;

[0035] Figure 3A calculation model of the circular-arc plane failure mode of the embodiment of the present application;

[0036] Figure 4 A stress model of the sliding rock mass of the embodiment of the present application;

[0037] Figure 5 A calculation model of the failure mode of the cutting surface of the embodiment of the present application;

[0038] Figure 6 A calculation model of the failure mode of the sliding-cutting of the embodiment of the present application;

[0039] Figure 7 A stress analysis model of the single-support-point anchor-type hanging pile in the circular-arc or circular-arc-plane failure mode of the embodiment of the present application;

[0040] Figure 8 A stress analysis model of the cantilever-type hanging pile in the circular-arc or circular-arc-plane failure mode of the embodiment of the present application;

[0041] Figure 9 A stress analysis model of the single-support-point anchor-type hanging pile in the cutting surface or sliding-cutting failure mode of the embodiment of the present application;

[0042] Figure 10 A stress analysis model of the cantilever-type hanging pile in the cutting surface or sliding-cutting failure mode of the embodiment of the present application;

[0043] Figure 11 A finite element model of the embodiment of the present application;

[0044] Figure 12 A comparison between the simulation results of the horizontal displacement of the pile body of the supporting pile and the monitoring data of the embodiment of the present application;

[0045] Figure 13 A failure result of the finite element simulation of the embodiment of the present application;

[0046] Figure 14 A shear stress of the finite element pile body of the embodiment of the present application;

[0047] Figure 15 A certain engineering foundation pit diagram of the embodiment of the present application;

[0048] Figure 16 A potential sliding surface of the foundation pit of the embodiment of the present application;

[0049] Figure 17 An optimized finite element model of the embodiment of the present application;

[0050] Figure 18 A failure mode of the foundation pit of the embodiment of the present application; Figure 15

[0051] ​Figure 19 This is a comparison diagram of the displacement of the suspended piles according to an embodiment of the present invention;

[0052] Figure 20 This is a design drawing of the support structure according to an embodiment of the present invention;

[0053] Figure 21 This is a schematic diagram of the HLC composite steel pile according to an embodiment of the present invention. Detailed Implementation

[0054] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0055] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0056] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0057] Figure 1 A schematic diagram illustrating the decision-making principle of the design parameters for the suspended piles in a stable rock mass dual-element foundation pit according to an embodiment of the present invention is provided. Based on... Figure 1 The decision-making method for the design parameters of the stable rock mass soil-rock dual-element foundation pit suspended pile in this embodiment may include the following steps S101~S103.

[0058] The specific implementation process of steps S101 to S103 is as follows:

[0059] Step S101: Based on the dual-element foundation pit soil and rock parameters, calculate the soil part anti-sliding force, soil part sliding force, rock mass resistance, and horizontal soil friction.

[0060] Step S102: The failure coefficient is obtained by summing the product of the soil partial sliding force, the failure mode propagation coefficient and the rock mass resistance, and the product of the soil friction deduction coefficient and the horizontal soil friction. The failure coefficient is obtained by quotienting the soil partial sliding force. The failure mode propagation coefficient and the soil friction deduction coefficient are 0 or 1.

[0061] Step S103: Determine the failure mode of the soil-rock dual-layer stratum based on the magnitude of the failure coefficient. Under the corresponding failure mode, combine the current soil and rock parameters of the foundation pit to calculate the corresponding parameters of the suspended piles when different types of suspended piles reach static equilibrium.

[0062] Under stable rock mass conditions, soil-rock dual-element foundation pits exhibit four failure modes: circular arc, circular arc-plane, tangential, and sliding shear. As the thickness of the overlying soil layer increases, the failure mode of soil-rock dual-element foundation pits gradually transitions from circular arc failure to circular arc-plane failure, tangential failure, and sliding shear failure.

[0063] (a) For circular arc failure mode:

[0064] When the excavation depth of the foundation pit is within the soil mass, the soil-rock dual foundation pit will experience circular arc sliding failure. The soil mass will generate overall failure sliding force and anti-sliding force. When the sliding force is greater than the anti-sliding force, it is the circular arc sliding mode of the soil foundation pit. If the radius of the circular arc is exactly on the soil-rock interface during the circular arc sliding, the circular arc may intersect with the excavation surface at the soil-rock interface. Figure 2 For the computational model of the circular failure mode, the resisting force and sliding force of the soil are calculated using the slice method. Soil slices... gravity The force is decomposed into tangential and normal forces along the center point of the sliding surface. The two components of the reaction force of the soil below the sliding surface are expressed as follows: and .

[0065] (1);

[0066] (2);

[0067] In the formula: For soil strips gravity, For soil strips cohesion, For soil strips The internal friction angle, For soil strips The angle between the sliding surface and the horizontal direction, For soil strips The length of the sliding surface; determining the geometric parameters of the sliding surface, circular arc surface. The mathematical expression is:

[0068] (3);

[0069] The weight of a soil strip can be expressed as :

[0070] (4);

[0071] In the formula: The unit weight of the soil. The thickness of the soil;

[0072] Other parameter expressions:

[0073] (5);

[0074] (6);

[0075] (7);

[0076] (8);

[0077] wherein: is the normal stress at the slip surface of the soil strip, is the radius of the slip surface, is the length of the lower slip surface of the soil strip, is the coordinate of the center of the circular arc when the soil strip slides in a circular arc, the partial anti-sliding force of the soil and the sliding force of the soil is generated by the tangential component of the gravity of the soil, is generated by the cohesion and internal friction of the soil, for the convenience of calculation, the function 、 、 the three functions;

[0078] (9);

[0079] (10);

[0080] (11);

[0081] (12);

[0082] (13);

[0083] wherein, is the angle between the lower slip surface of the soil and the horizontal direction; is the internal friction angle of the soil; is the cohesion of the soil strip. Since the application of the analytical solution needs to determine the center and radius of the circular arc, the slip curve of the slope is obtained by applying the slip line field method, the center coordinate

[0084] and the radius are determined. When , the soil part is in sliding failure.

[0085] (b) for the circular arc-plane failure mode:

[0086] The foundation pit is excavated to the soil-rock interface and below, the overlying soil body slides to the rock surface in a circular arc, at this time the upper soil body is constrained by the rock body, when the sliding force is greater than the soil body sliding resistance and the soil-rock interface friction resistance, circular arc-plane failure occurs. Figure 3 The calculation model for the circular arc-plane failure mode.

[0087] Residual sliding force of the soil body partial circular arc sliding , which is calculated by the strip method:

[0088] (14);

[0089] The stress analysis of the rock body is shown in Figure 4 , the angle between the sliding surface and the horizontal plane is , the rock body is partially subjected to the normal force perpendicular to the sliding surface , the sliding resistance parallel to the sliding surface , the combined force of the gravity of the soil-rock , and the length of the rock body sliding surface is ; the limit equilibrium analysis is performed on the rock body part.

[0090] The gravity expression of the rock body is:

[0091] (15);

[0092] The limit equilibrium analysis is performed on the rock body part, and the sliding resistance of the rock body cutting angle is :

[0093] (16);

[0094] The sliding force of the rock body cutting angle is :

[0095] (17);

[0096] The expression of the rock body resistance is: :

[0097] (18);

[0098] In the formula: is the specific gravity of the rock body, is the internal friction angle of the rock body, is the cohesion of the rock body; when the rock body is in the limit equilibrium state , the simultaneous expressions of formula (16), (17), and (18) are obtained:

[0099] (19);

[0100] When the lower stable rock body is subjected to a force of the failure range the expression:

[0101] (20);

[0102] When , the overall anti-sliding force of the rock mass is greater than the sliding force of the rock mass, the rock mass is in a stable state, no corner failure occurs, and the foundation pit is in a circular-arc-plane failure mode.

[0103] (c) For the cutting surface failure mode:

[0104] When the foundation pit excavation working condition enters the depth of the rock mass, the overlying soil circular-arc slides to the surface of the rock mass, and when the shear strength of the rock mass is insufficient to resist the soil downward force and the shear strength of the rock mass is just enough to resist the downward force of the upper soil, the rock mass fails along the extension line of the soil circular-arc failure surface. Figure 5 is the calculation model under the cutting surface failure mode.

[0105] The expression of the rock mass resistance is the same as formula (18), and the expression of the residual downward force of the soil partial circular-arc sliding is formula (14). When , the rock mass is in a stable state, the shear strength of the rock mass is just enough to resist the downward force of the upper soil, and no corner failure occurs.

[0106] (d) For the sliding-cutting failure mode:

[0107] When the excavation depth of the foundation pit is large and the upper soil is thick, the soil downward force decays to a certain degree along the soil-rock interface, the residual downward force is just in shear balance with the rock mass wedge, and circular-arc-plane-corner failure occurs. Figure 6 is the calculation model under the sliding-cutting failure mode.

[0108] The expression of the rock mass resistance is the same as formula (18), and the expression of the residual downward force of the soil partial circular-arc sliding is formula (14). When , the overall downward force generated when the overlying soil slides is greater than the rock mass resistance , at this time the rock mass is in a non-stable state, corner failure occurs, and the failure mode is sliding-cutting failure; wherein, is the horizontal soil friction resistance.

[0109] When only the soil is assessed for failure mode, the failure mode propagation factor is 0; when the rock mass resistance is added to the assessment of the soil failure mode, the failure mode propagation factor is 1; when the horizontal soil friction is deducted from the failure mode assessment, the soil friction deduction factor is 1; when the horizontal soil friction is not deducted from the failure mode assessment, the soil friction deduction factor is 0.

[0110] When both the failure mode propagation coefficient and the soil friction deduction coefficient are 0: when the failure coefficient is greater than or equal to 1, no failure occurs or the previous stage failure occurs; when the failure coefficient is less than 1, the failure mode is circular arc or circular arc-plane failure.

[0111] When the failure mode propagation factor is 1 and the soil friction deduction factor is 0: when the failure factor is greater than or equal to 1, the failure mode is circular arc or circular arc-plane failure; when the failure factor is less than 1, the failure mode is shear failure or sliding failure.

[0112] When both the failure mode propagation coefficient and the soil friction deduction coefficient are 1: when the failure coefficient is greater than or equal to 1, the failure mode is shear failure; when the failure coefficient is less than 1, the failure mode is sliding failure.

[0113] In the determination of failure modes of soil-rock dual-element strata, a failure coefficient is introduced. S Quantitatively characterize its damage mode. When S When ≥1, it means that the anti-slip force is sufficient to counteract the sliding force, and no failure occurs or the previous stage of failure occurs; conversely, when S When the value is less than 1, it means that the sliding force dominates, and failure will occur. For different failure modes, a failure mode propagation coefficient is introduced. With soil friction deduction factor When making distinctions, only the soil is assessed for failure mode. When adding rock mass resistance ; When deducting horizontal soil friction Based on different coefficient values, S The loads and constraints imposed on the values ​​are different. , , It is based on the damage coefficient under different damage modes. S The value expression is as follows:

[0114] (twenty one);

[0115] use S The process of determining the destruction mode based on the value is shown in Table 1.

[0116] Table 1. Damage Mode Judgment Table;

[0117]

[0118] In the circular or circular-plane failure mode, the single support point anchor type of the hanging foot pile is subjected to the soil pressure generated by the unloading of the soil outside the pit , the transverse support force provided by the anchor rod , and the rock shoulder resistance provided by the rock shoulder ; after excavation, the hanging foot pile is in a state of force balance, and the stress analysis model of the single support point anchor type of the hanging foot pile is shown in Figure 7 .

[0119] The partial active earth pressure of the soil is expressed as:

[0120] (22);

[0121] The horizontal resistance provided by the rock shoulder is:

[0122] (23);

[0123] When the hanging foot pile is in static equilibrium, the static equilibrium relationship of the three is:

[0124] (24);

[0125] In the formula: is the self-stable height of the soil in Rankine's earth pressure calculation; is the active earth pressure coefficient, is the width of the rock shoulder, is the depth of the rock-embedded when the hanging foot pile is in static equilibrium, The expression of

[0126] (25);

[0127] In the circular or circular-plane failure mode, the bending moment and shear force V of the hanging foot pile are calculated as follows:

[0128] (26);

[0129] (27);

[0130] In the formula: L is the length of the hanging foot pile, is the length of the anchor rod to the top of the pile, is the distance between the calculation section and the rock shoulder resistance, is the distance between the calculation section and the resultant force of the soil pressure.

[0131] The embedded depth of the single-layer anchor should meet the stability requirement of the following formula:

[0132] (28);

[0133] When the hanging pile is cantilevered, the stability of the embedded depth does not need to be considered , as shown in FIG. 4B, and the embedded depth should meet the stability requirement of the embedded depth: Figure 8

[0134] (29);

[0135] When the failure mode is circular arc failure or circular arc-plane failure, the rock mass is stable and does not fail, and the embedded depth of the hanging pile only needs to meet the force balance condition, and the length of the hanging pile . Wherein, is the height of the soil; is the distance between the calculation section and the rock shoulder resistance; is the distance between the calculation section and the resultant force of the earth pressure; is the distance between the rock shoulder resistance and the pile bottom; is the distance between the resultant force of the earth pressure and the pile bottom; is the embedded stability safety factor; is the active earth pressure of the soil part; is the rock shoulder resistance provided by the rock shoulder.

[0136] In the cutting surface or sliding cutting failure mode, the hanging pile is subjected to the friction force T on the soil-rock interface in addition to the earth pressure and the rock shoulder resistance, and the force analysis model of the single-point anchor hanging pile is shown in FIG. 4C; Figure 9

[0137] The expression of the rock mass failure height is obtained from the geometric relationship:

[0138] (30);

[0139] The expression of the friction force T on the soil-rock interface is:

[0140] (31);

[0141] Wherein, is the pressure of the soil; is the angle between the soil-rock interface and the horizontal direction; is the specific gravity of the soil.

[0142] In the cutting surface or sliding cutting failure mode, the bending moment and the shear force V ​​is calculated as follows:

[0143] (32);

[0144] (33);

[0145] is the distance between the friction of the rock-soil mass and the pile end in the case of single fulcrum anchor type of the overhanging pile; is the transverse support force provided by the i th anchor rod.

[0146] The embedment depth of the single fulcrum anchor type of the overhanging pile should meet the stability requirements of the following formula:

[0147] (34);

[0148] When the overhanging pile is in cantilever type, the does not need to be considered, the stress analysis model of the cantilever type of the overhanging pile is shown in Figure 10 , and the embedment depth should meet the requirements of the embedment stability:

[0149] (35);

[0150] When the failure mode is the cutting surface or the sliding cutting failure, the rock mass is damaged, and at this time, the rock-embedded depth of the overhanging pile not only needs to meet the stress balance condition, but also needs to meet the stability requirements of resisting the damage of the rock mass, so the rock-embedded depth is selected as the maximum value between , , and the length of the overhanging pile is .

[0151] wherein, is the rock mass damage height; is the soil height; is the distance between the calculation section and the rock shoulder resistance; is the distance between the calculation section and the resultant force of the earth pressure; is the distance between the rock shoulder resistance and the pile bottom; is the distance between the resultant force of the earth pressure and the pile bottom; is the embedment stability safety factor; is the active earth pressure of the soil part; is the rock shoulder resistance provided by the rock shoulder; is the friction on the soil-rock interface; is the length of the anchor rod to the pile top; is the distance between the friction of the rock-soil mass and the pile end in the case of single fulcrum anchor type of the overhanging pile;

[0152] When the hanging pile meets the static balance condition, the hanging pile is selected, and the stability of the soil-rock dual foundation pit is calculated by using the strip method according to the corresponding failure mode.

[0153] In a certain soil-rock dual deep foundation pit project, the overlying soil layer is silty clay with a thickness of about 8.5m, and the underlying rock mass is tuff. The supporting pile is 34m long, and the open excavation method is used for construction. In this embodiment, a finite element model is established using PLAXIS 3D software. The steel pipe pile is simulated by using the equivalent moment of inertia principle to use the reduced thickness elastic plate. It should be noted that in other embodiments, other existing software can also be used to establish a finite element model.

[0154] The contact between soil, rock and elastic plate is simulated by using interface elements. The crown beam, waist beam and anchoring segment are simulated by using Embedded pile elements. The anchor cable is simulated by using point-to-point anchor elements. The HSS model, which is more accurate in expressing the stress-strain path of soil, is selected to simulate the soil layer, and the Mohr-Coulomb model is used to simulate the rock mass. The finite element model is shown in Figure 11 .

[0155] Table 2 Rock mass parameters

[0156]

[0157] Select monitoring data and finite element simulation results for comparison. Process a and process b are excavation to the soil-rock interface and excavation to the 25m pit bottom, respectively. The comparison of the simulation results of the horizontal displacement of the supporting pile body with the monitoring data is shown in Figure 12 . Both are basically consistent, proving that the numerical model parameters and element selection are scientific, and the subsequent research results are reasonable.

[0158] According to the value judgment method in Table 2 S , the failure mode is judged, S The value calculation requires related data such as Table 3. The failure mode is circular sliding, and the finite element simulation failure mode is shown in Figure 13 . Substitute the above stratum parameters and supporting parameters into equations (22), (23), (24) and (27) to calculate the limit equilibrium depth of 5.26m. The calculation results are shown in Table 3. The finite element simulation failure results and the shear stress of the pile body are shown in Figure 13 and Figure 14 .

[0159] Table 3 Calculation results

[0160]

[0161] The simulation of shear stress results according to the finite element method shows that the failure mode under the stratum condition is circular-arc sliding, and the shear force of the hanging foot pile at 13.6 m is 0, with an error of 0.16 m between the theoretical calculation of 13.76 m, and an error rate of about 1.2%, verifying the rationality of the theoretical derivation of the failure mode and the static force balance calculation.

[0162] As Figure 15 shown, a certain soil-rock dual foundation pit is intended to be excavated to a depth of 13.6 m, of which the soil is 7.6 m and the rock is 6 m. The foundation pit safety level is two, and the pile top displacement control value is 20 mm. The stratum condition from top to bottom is miscellaneous fill, loess, silty clay, dissolved and broken dolomite, and medium weathered dolomite. According to the survey report and regional geological analysis, the underlying rock mass of this foundation pit is stable, and the hanging foot pile support is intended to be selected. The foundation pit support design parameters are shown in Table 4.

[0163] Table 4 Stratum parameters;

[0164]

[0165] Based on the parameters of the above-mentioned engineering example in a certain area, the overlying soil layer is simplified as homogeneous silty clay, and the underlying rock mass is medium weathered dolomite combined with the proposed failure coefficient R value failure mode criterion, the failure mode under the stratum is judged, and the calculation results are shown in Table 5.

[0166] Table 5 Failure mode calculation and determination results;

[0167] Calculation results Numerical values Minimum safety factor 0.95 Q 抗滑 ]]> ​ 450.65 kN / m <![CDATA[ Q 下滑 ]]> 490.70 kN / m S 1]]> ​ 0.95 [S2] 1.2 Failure mode Circular arc failure

[0168] For example, the safety factor of the foundation pit is calculated using the matlab program, and the potential sliding surface is searched, and the minimum sliding safety factor is 0.92. The potential sliding surface of the foundation pit is shown in Figure 16 .

[0169] According to the deformation requirement, the hanging foot pile is designed, the soil pressure is triangular load, and the stiffness calculation results are shown in Table 6. The φ800 reinforced concrete pile, the rock shoulder width is 1 m, the static force balance of the hanging foot pile is calculated h 1=1.3m, the rock-embedded depth is 1.5m, and the total length of the hanging foot pile is 8.3m.

[0170] Table 6 Stiffness calculation results;

[0171]

[0172] Based on the circular-arc failure mode of the foundation pit, the above-mentioned hanging foot pile is selected, and the overall stability safety factor K of the foundation pit is calculated according to the building foundation and slope engineering design specification:

[0173] (36);

[0174] (37);

[0175] wherein: is the diameter of the support pile; is the axial distance between support piles; is the design value of the tensile strength of concrete; is the cross-sectional width of the pile body; is the effective height of the cross-section of the pile body; is the design value of the tensile strength of the stirrup; is the cross-sectional area of the stirrup of the pile body; is the shear resistance provided by the waterproof curtain of the enclosure member to the failure sliding soil body; is the spacing of the stirrup along the pile body.

[0176] The support pile adopts a stirrup of φ10@150 and a main reinforcement of 12φ20, and the pile spacing is 1.5 m. The overall stability safety factor of the foundation pit is calculated as follows: K ;

[0177] The stability safety factor meets the overall stability safety factor of the secondary support structure, indicating that the foundation pit is in a safe state under the support condition.

[0178] A three-dimensional finite element model including soil, rock, suspended pile, support structure, etc. is established by using PLAXIS 3D software. According to the performance of the "depth effect", based on the experience of a fluvial geomorphic unit foundation pit engineering, the soil-rock bimodal foundation pit with a soil depth of not more than 18 m uses the MC model for the soil-rock constitutive relationship. The optimized finite element model is shown in Figure 17 , and the failure mode of the foundation pit is shown in Figure 18 .

[0179] Through the simulation of the finite element software, it can be obtained that the failure mode under the soil-rock stratum condition is circular arc failure; the stress calculation results of the optimized suspended pile are basically consistent, and the foundation pit is in a stable state.

[0180] The displacement of the suspended pile is calculated according to the stiffness of the suspended pile, and the calculation results are compared with the numerical simulation and field monitoring. The comparison results are shown in Figure 19 . It can be seen that the results obtained by the three methods are basically consistent, proving that the selection is reasonable.

[0181] ​The all-recycled steel sheet pile is used to replace the reinforced concrete hanging foot pile, which can reduce the carbon emission of the reinforced concrete pile in terms of reduction of production, recycling and reuse, etc. The maximum recycling number of the enclosure structure is 6, and the material loss rate is 16.67% each time. The carbon emission of material production and material transportation of a single reinforced concrete pile and HLC (i.e. H-shaped steel and Larsen steel sheet pile combination) steel sheet pile is calculated according to the existing known standard building carbon emission calculation method, and the calculation results are shown in Table 7.

[0182] Table 7 Carbon emission of different materials hanging foot pile;

[0183]

[0184] When the reinforced concrete pile is used for support, the bending stiffness of the hanging foot pile is much larger than the minimum required stiffness for support. The bending stiffness of the HLC steel sheet pile combined with H700x300x13x24 and IV Larsen steel sheet pile is , and the steel sheet pile is used for support, which can be quickly constructed, and the support structure can be recycled, which is more in line with the demand of green development. The displacement of the HLC steel sheet pile is calculated:

[0185]

[0186] The calculation results prove that the deformation of the combined steel sheet pile can meet the requirements of the foundation pit deformation, and can be used for support. The support structure is shown in Figure 20 , and the HLC cross section is shown in Figure 21 .

[0187] In one or more embodiments, a decision system for stabilizing rock-soil dual foundation pit hanging foot pile design parameters is also provided, which can be realized in software. The decision system for stabilizing rock-soil dual foundation pit hanging foot pile design parameters includes the following software modules:

[0188] A mechanical parameter calculation module is used to calculate the soil part sliding resistance, soil part sliding force, rock resistance and horizontal soil friction based on the soil-rock parameters of the dual foundation pit.

[0189] A failure coefficient calculation module is used to obtain the failure coefficient by dividing the sum of the product of the soil part sliding resistance, the failure mode expansion coefficient and the rock resistance, and the product of the soil friction resistance deduction coefficient and the horizontal soil friction, by the soil part sliding force. The values of the failure mode expansion coefficient and the soil friction resistance deduction coefficient are 0 or 1.

[0190] A hanging foot pile parameter calculation module is used to determine the failure mode of the soil-rock dual stratum according to the size of the failure coefficient, and calculate the corresponding hanging foot pile parameters of different types of hanging foot piles when reaching static equilibrium under the corresponding failure mode in combination with the current foundation pit soil-rock parameters. ​

[0191] It should be noted that each module in the stable rock-soil dualistic foundation pit underpinning pile design parameter decision system of the embodiment of the present application corresponds to each step in the stable rock-soil dualistic foundation pit underpinning pile design parameter decision method of the above embodiment one by one, and the specific implementation process is the same, which will not be repeated here.

[0192] The structure of the electronic device of the embodiment of the present application will be described in detail below. The electronic device provided by the embodiment of the present application includes at least one processor, a memory, a user interface and at least one network interface. Each component in the stable rock-soil dualistic foundation pit underpinning pile design parameter decision system is coupled together through a bus system. It can be understood that the bus system is used to realize the connection and communication between the components. In addition to the data bus, the bus system also includes a power bus, a control bus and a state signal bus.

[0193] The user interface can include a display, a keyboard, a mouse, a trackball, a click wheel, a key, a button, a touchpad or a touch screen, etc.

[0194] It can be understood that the memory can be a volatile memory or a non-volatile memory, and can also include both volatile and non-volatile memories. The memory in the embodiment of the present application can store data to support the operation of the terminal. Examples of these data include any computer programs for operating on the terminal, such as operating systems and application programs. The operating system contains various system programs, such as framework layers, core library layers, driver layers, etc., for implementing various basic services and processing hardware-based tasks. The application program can include various application programs.

[0195] In some embodiments, the stable rock-soil dualistic foundation pit underpinning pile design parameter decision system provided by the embodiment of the present application can be implemented in a combination of software and hardware. As an example, the stable rock-soil dualistic foundation pit underpinning pile design parameter decision system provided by the embodiment of the present application can be a processor in the form of a hardware decoding processor programmed to execute the stable rock-soil dualistic foundation pit underpinning pile design parameter decision method provided by the embodiment of the present application. For example, the processor in the form of a hardware decoding processor can use one or more application-specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), complex programmable logic devices (CPLDs), field-programmable gate arrays (FPGAs) or other electronic components.

[0196] As an example, the processor 301 can be an integrated circuit chip with signal processing capability, e.g., a general purpose processor, a Digital Signal Processor (DSP), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, etc. The general purpose processor can be a microprocessor, or any conventional processor, etc.

[0197] As an example, the processor 301 can be an integrated circuit chip with signal processing capability, e.g., a general purpose processor, a Digital Signal Processor (DSP), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, etc. The general purpose processor can be a microprocessor, or any conventional processor, etc.

[0198] The memory in the embodiments of the present application is used to store various types of data to support the operation of the decision system for stabilizing the design parameters of the soil-rock dual foundation pit hanging foot pile, or to store program codes for executing the methods shown in the embodiments of the present application. Figure 1 Examples of these data include any executable instructions for operating on the decision system for stabilizing the design parameters of the soil-rock dual foundation pit hanging foot pile, such as executable instructions, and the program implementing the decision method for stabilizing the design parameters of the soil-rock dual foundation pit hanging foot pile in the embodiments of the present application can be included in the executable instructions.

[0199] In particular, according to the embodiments of the present application, the processes described above with reference to the flowcharts can be implemented as a computer software program. For example, the embodiments of the present application include a computer program product comprising a computer program carried on a computer readable medium, the computer program containing program codes for executing the methods shown. Figure 1 In such embodiments, the computer program can be downloaded and installed from a network by a communication part, and / or installed from a detachable medium. When the computer program is executed by the central processing unit, various functions defined in the device of the present application are executed.

[0200] The computer program instructions can also be loaded onto a computer, other programmable data processing apparatus, or other processing device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other processing device to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions specified in the flowchart block or blocks. Figure 1 The flowchart and / or block diagram in the drawings illustrate the architecture, functionality, and operation of possible implementations of apparatuses and methods according to various embodiments. In this regard, each flowchart and / or block diagram can represent a method, apparatus and / or computer program product. Figure 1 The flowchart and / or block diagrams in the drawings illustrate the architecture, functionality, and operation of possible implementations of apparatuses and methods according to various embodiments. In this regard, each flowchart and / or block diagram can represent a method, apparatus and / or computer program product.

[0201] The above merely provides the preferred embodiment of the present application and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for calculating the design parameters of a stable rock-soil dual foundation pit underpinning pile, characterized in that, The method comprises the following steps: Based on the soil-rock parameters of the two-element foundation pit, the soil partial sliding resistance, the soil partial sliding force, the rock resistance and the horizontal soil friction are calculated; The product of the soil partial sliding resistance, the failure mode expansion coefficient and the rock resistance, the product of the soil friction deduction coefficient and the horizontal soil friction are added, and then the quotient of the sum and the soil partial sliding force is obtained to obtain the failure coefficient; the failure mode expansion coefficient and the soil friction deduction coefficient are 0 or 1; When only the soil is subjected to failure mode judgment, the failure mode expansion coefficient is 0; When the soil is subjected to failure mode judgment and the rock resistance is added, the failure mode expansion coefficient is 1; When the horizontal soil friction is deducted for failure mode judgment, the soil friction deduction coefficient is 1; When the horizontal soil friction is not deducted for failure mode judgment, the soil friction deduction coefficient is 0; According to the size of the failure coefficient, the failure mode of the soil-rock two-element stratum is judged, and under the corresponding failure mode, the soil-rock two-element foundation pit is calculated to obtain the corresponding parameters of the hanging foot pile of different types when the hanging foot pile reaches static equilibrium.

2. The method for calculating the design parameters of the soil-rock bimodal foundation pit underpinning pile of the stable rock mass according to claim 1, characterized in that, When the failure mode expansion coefficient and the soil friction deduction coefficient are both 0, when the failure coefficient is greater than or equal to 1, no failure or the last stage failure occurs; when the failure coefficient is less than 1, the failure mode is circular arc or circular arc-plane failure.

3. The method for calculating the design parameters of the rock-soil dual foundation pit underpinning pile of the stable rock mass according to claim 1, characterized in that, When the failure mode expansion coefficient is 1 and the soil friction deduction coefficient is 0, when the failure coefficient is greater than or equal to 1, the failure mode is circular arc or circular arc-plane failure; when the failure coefficient is less than 1, the failure mode is cross-section failure or sliding failure.

4. The method for calculating the design parameters of the rock-soil dual foundation pit underpinning pile of the stable rock mass according to claim 1, characterized in that, When the failure mode expansion coefficient and the soil friction deduction coefficient are both 1, when the failure coefficient is greater than or equal to 1, the failure mode is cross-section failure; when the failure coefficient is less than 1, the failure mode is sliding failure.

5. The method for calculating the design parameters of the rock-soil dual foundation pit overhanging pile according to claim 1, characterized in that, When the failure mode is circular arc or circular arc-plane failure, the rock-socketed depth of the single-support-point anchor-lifting pile The force balance condition to be met is: ; the rock-socketed depth of the cantilevered anchor-lifting pile The force balance condition to be met is: ; the length of the anchor-lifting pile ; wherein, H is the height of the soil mass; L is the distance between the calculated section and the rock shoulder resistance; L is the distance between the calculated section and the resultant of the earth pressure; L is the distance between the rock shoulder resistance and the pile bottom; L is the distance between the resultant of the earth pressure and the pile bottom; K is the factor of safety for the embedded stability; P is the active earth pressure of the soil mass; R is the rock shoulder resistance provided by the rock shoulder.

6. The method for calculating the design parameters of the soil-rock bimodal foundation overhanging pile of the stable rock mass according to claim 1, characterized in that, When the failure mode is the section failure or the sliding shear failure, the rock-socketed depth of the single-fulcrum anchor-lifting pile The force balance condition to be met is: When the failure mode is the section failure or the sliding shear failure, the rock-socketed depth of the single-fulcrum anchor-lifting pile The force balance condition to be met is: The length of the anchor-lifting pile ​ wherein, is the height of rock mass failure; is the height of soil mass; is the distance between the calculated section and the rock shoulder resistance; is the distance between the calculated section and the resultant of the earth pressure; is the distance between the rock shoulder resistance and the pile bottom; is the distance between the resultant of the earth pressure and the pile bottom; is the embedded stability safety factor; is the active earth pressure of the soil mass portion; is the rock shoulder resistance provided by the rock shoulder; is the friction on the rock-soil interface; is the length of the anchor to the top of the pile; is the distance of the rock-soil friction from the pile end in the case of a cantilevered footing pile.

7. The method for calculating the design parameters of the soil-rock bimodal foundation overhanging pile of the stable rock mass according to claim 1, characterized in that, When the hanging foot pile satisfies the static equilibrium condition, the hanging foot pile is selected, and the stability of the soil-rock two-element foundation pit is calculated by using the strip method according to the corresponding failure mode.

8. A system for calculating the design parameters of a soil-rock dual foundation pit underpinning pile of a stable rock mass, characterized in that, The method for calculating the design parameters of the hanging foot pile of the stable rock-soil two-element foundation pit according to any one of claims 1-7 comprises: A mechanical parameter calculation module is configured to calculate the soil partial sliding resistance, the soil partial sliding force, the rock resistance and the horizontal soil friction based on the soil-rock parameters of the two-element foundation pit; A failure coefficient calculation module is configured to calculate the failure coefficient by adding the product of the soil partial sliding resistance, the failure mode expansion coefficient and the rock resistance, the product of the soil friction deduction coefficient and the horizontal soil friction, and then dividing the sum by the soil partial sliding force; the failure mode expansion coefficient and the soil friction deduction coefficient are 0 or 1; A hanging foot pile parameter calculation module is configured to judge the failure mode of the soil-rock two-element stratum according to the size of the failure coefficient, and calculate the corresponding parameters of the hanging foot pile of different types when the hanging foot pile reaches static equilibrium under the corresponding failure mode in combination with the current soil-rock parameters of the foundation pit.

9. A computer readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to realize the steps in the method for calculating the design parameters of the hanging foot pile of the stable rock-soil two-element foundation pit according to any one of claims 1-7.

10. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the steps in the method for calculating the design parameters of the soil-rock dual foundation pit underpinning pile of the stable rock mass according to any one of claims 1-7 when executing the program.

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