Excavation and support construction method for underground powerhouse

Abstract

The invention provides an underground powerhouse excavation support construction method, which relates to the field of underground powerhouse construction, and comprises the following steps: S1, measuring and analyzing surrounding rock parameters of a rock sample in a target area of an underground powerhouse, including the crustal stress environment, the lithology of surrounding rock and the strength parameter of the surrounding rock; and S2, determining the supporting strength based on the surrounding rock parameters. Through the cooperation of the structures, firstly, specific support measures required under different geological conditions can be evaluated more accurately through a regression fitting relation among a system anchor rod, a pre-stressed anchor cable support strength, a surrounding rock strength stress ratio and a plant excavation span; secondly, the surrounding rock support index of the underground powerhouse can be defined, and the matching degree between the support design and the theoretical calculation value in the actual engineering can be intuitively reflected by the dimensionless index; and thirdly, the risks of local instability, collapse or excessive deformation and the like caused by insufficient supporting strength are effectively prevented, and the personnel safety and the structural stability in the construction process are guaranteed.

Description

Technical Field

[0001] The invention relates to the field of underground plant construction, and in particular to an underground plant excavation and support construction method. Background Art

[0002] Appropriate support design for underground powerhouses is a key engineering and technical issue to ensure the safe construction and operation of underground projects. The surrounding rock support structure of underground powerhouses generally includes shotcrete, ordinary anchors, prestressed anchors and prestressed anchor cables. However, due to the complexity of the surrounding rock medium itself, the deformation characteristics and reinforcement mechanism of the surrounding rock under complex stress conditions cannot be fully understood at present, making the relevant theories and specifications for surrounding rock reinforcement immature. The support of underground powerhouses is still in the state of "empirical design and empirical construction" to a considerable extent.

[0003] In addition, the underground powerhouse is located in a different geostress environment, and the rock properties and strength of the surrounding rock are different, so the support strength required to maintain the stability of the surrounding rock also changes. Insufficient support strength will cause local instability, collapse, or excessive deformation of the surrounding rock, or even overall damage, while excessive support strength will cause unnecessary waste. Summary of the invention

[0004] In view of the shortcomings of the above-mentioned prior art, the technical problem to be solved by the present invention is to provide an underground plant excavation support construction method, which can accurately define the underground plant surrounding rock support index through the regression fitting relationship between the system anchor rods, prestressed anchor cable support strength and surrounding rock strength stress ratio, and the plant excavation span.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: the present invention provides an underground powerhouse excavation support construction method, comprising the following steps: S1. Measure and analyze the surrounding rock parameters of rock samples in the target area of ​​the underground powerhouse, including the in-situ stress environment, lithology of the surrounding rock and strength parameters of the surrounding rock; S2. Determine the support strength based on surrounding rock parameters; Among them, the support strength is determined by the regression fitting relationship between the system anchor, prestressed anchor cable and surrounding rock strength stress ratio and the powerhouse excavation span, and a regression fitting model is established through the regression fitting relationship; S3. Define the dimensionless system anchor support index and prestressed anchor support index , which is used to reflect the relative relationship between the actual support strength and the empirical formula.

[0006] In the preferred solution, in step S1, the reverse locking force formed by the elastic recovery deformation of the system anchor on the surrounding rock is determined according to the local ground stress environment, the lithology of the surrounding rock and the strength parameters of the surrounding rock, and the support effect of the system anchor is reflected by adjusting the shear strength parameters of the surrounding rock; Then the shear strength parameter of the surrounding rock after the system anchor is applied is determined by the following formula:

[0007] Based on formula (1), the cohesion increment of the surrounding rock after the system anchor is applied is Determined by the following formula:

[0008] in, To increase the cohesion of the surrounding rock before anchoring, is the internal friction angle of the surrounding rock before anchoring; is the shear strength of the anchor rod, is the cross-sectional area of ​​the anchor rod, is the vertical and horizontal spacing of anchor rods, and the group anchor effect coefficient is the dimensionless coefficient, is the anchor diameter; Group anchor effect coefficient The value range is 2.0~5.0.

[0009] In the preferred solution, in step S2, the prestressed anchor cable applies prestress to the surrounding rock to increase the confining pressure of the cave wall, corresponding to the shear stress The intercept difference is the increment of surrounding rock cohesion provided by the anchor cable. , the rock friction coefficient before and after reinforcement When the prestress N is applied and the spacing is a×b, the cohesion increment of the surrounding rock after the prestressed anchor cable is applied is Determined by the following formula:

[0010] in, is the internal friction angle of the surrounding rock before anchoring.

[0011] In the preferred solution, in step S2, the cohesion increment of the surrounding rock under the action of the system anchor is calculated based on formula (2): , the cohesion increment of the surrounding rock under the action of the system anchor Strength-stress ratio The relationship between is obtained by curve fitting and the value is =3.5, =200MPa, then the system anchor support strength Determined by the following formula:

[0012] Among them, the strength stress ratio is a dimensionless constant.

[0013] In the preferred solution, based on formula (4), it can be concluded that, under the premise of satisfying the stability of the surrounding rock, the decrease of the surrounding rock strength and the increase of the ground stress will increase the support strength accordingly, and its growth rate is proportional to the strength-stress ratio. The relationship between is nonlinear and is determined by the following formula:

[0014] In the preferred solution, the cohesion increment of the surrounding rock under the action of the system anchor is Strength-stress ratio And the excavation span of the plant The relationship between is obtained by surface fitting, then the system anchor support strength Determined by the following formula:

[0015] Among them, the cohesion increment of surrounding rock is Excavation span of the plant It is approximately linear and changes with the excavation span of the plant. The increase of strength stress ratio increases based on formula (6). When the system anchor support strength Strength-stress ratio The -2 singularity is expressed as: .

[0016] In the preferred solution, in step S2, the cohesion increment of the surrounding rock under the action of the prestressed anchor cable is calculated based on formula (3): , the cohesion increment of surrounding rock under the action of prestressed anchor cables Strength-stress ratio The relationship between is obtained by curve fitting and the value is =3.5, then the strength of prestressed anchor cable support Determined by the following formula:.

[0017]

[0018] In the preferred solution, based on formula (7), it can be concluded that the strength of the prestressed anchor cable support is Strength-stress ratio decreases with the increase of and is determined by the following formula:

[0019] In the preferred solution, the cohesion increment of the surrounding rock under the action of the prestressed anchor cable is Strength-stress ratio And the excavation span of the plant The relationship between is obtained by surface fitting, then the strength of prestressed anchor cable support is Determined by the following formula:

[0020] Among them, the cohesion increment of surrounding rock under the action of prestressed anchor cable is Excavation span of the factory building increases with the increase of When it is greater than a certain value, the cohesion increment of the surrounding rock under the action of the prestressed anchor cable Excavation span of the plant Approximately linear relationship.

[0021] In the preferred solution, in step S3, in order to reflect the relative relationship between the actual support strength and the empirical formula, a dimensionless support index is proposed; Defining the dimensionless system bolting index Determined by the following formula:

[0022] Wherein, the numerator is the calculated value of the support strength of the system anchor based on formula (2), and the denominator is the support strength calculated based on the empirical fitting formula (4) or (6); Definition of dimensionless prestressed anchor cable support index Determined by the following formula:

[0023] The numerator is the calculated value of the support strength of the prestressed anchor cable based on formula (3), and the denominator is the support strength calculated based on the empirical fitting formula (7) or (9).

[0024] The present invention provides an underground powerhouse excavation support construction method, which can achieve the following beneficial effects through the cooperation between the above structures: First, the specific support measures required under different geological conditions can be more accurately evaluated through the regression fitting relationship between the support strength of system anchors and prestressed anchor cables and the surrounding rock strength stress ratio and the excavation span of the powerhouse, which can avoid the problem of overly conservative or overly radical support design due to lack of experience; Second, it can define the surrounding rock support index of underground powerhouses. The dimensionless index can directly reflect the matching degree between the support design in the actual project and the theoretical calculation value. Based on this index, the design scheme can be adjusted in time to ensure that the safety requirements are met while avoiding unnecessary material consumption and construction costs caused by excessive support, thus achieving a balance between economic benefits and safety. Third, it effectively prevents the risks of local instability, collapse or excessive deformation caused by insufficient support strength, and ensures the safety of personnel and structural stability during the construction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 This is the main structural diagram of the hierarchical excavation of the present invention; Figure 2 It is a schematic diagram of the force of the prestressed anchor cable reinforcement mechanism in the present invention; Figure 3 It is a schematic diagram of the relationship between the cohesion increment and the strength stress ratio of the surrounding rock reinforced by the system anchor in the present invention; Figure 4 It is a schematic diagram of the relationship between the cohesion increment of the surrounding rock reinforced by the system anchor rod and the strength stress ratio and the excavation span of the powerhouse in the present invention; Figure 5 It is a schematic diagram of the relationship between the cohesion increment and the strength-stress ratio of the surrounding rock reinforced by the prestressed anchor cable in the present invention; Figure 6 It is a schematic diagram of the relationship between the cohesion increment and strength-stress ratio of the surrounding rock reinforced by the prestressed anchor cable and the excavation span of the powerhouse in the present invention; Figure 7 It is a schematic diagram of the distribution range of anchor support index of each underground plant system in the present invention; Figure 8 It is a schematic diagram of the distribution range of the prestressed anchor cable support index of various underground workshops in the present invention. DETAILED DESCRIPTION

[0026] In order to better understand the purpose, structure and function of the present invention, the embodiments and features in the embodiments of the present application can be combined with each other without conflict. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0027] like Figure 1 As shown, the present invention relates to an underground powerhouse excavation support construction method, which aims to solve the problem that the support strength required to maintain the stability of the surrounding rock varies due to the different ground stress environments of the underground powerhouse and the different lithology and strength of the surrounding rock. The surrounding rock support index of the underground powerhouse is defined by the regression fitting relationship between the system anchor rods, prestressed anchor cables, the surrounding rock strength stress ratio and the powerhouse excavation span, so that the rationality of the surrounding rock support can be quantitatively evaluated. The following are the specific implementation steps of the method: S1, such as Figure 1 As shown in the figure, the main powerhouse, main transformer room, tailgate room and tailwater connection tunnel were simulated in stages. The staged excavation characteristics are summarized in the following table: Table 1 Graded excavation table of Shuangjiangkou underground powerhouse

[0028] Table 2 Layered excavation characteristics of the powerhouse on the left bank of Shuangjiangkou

[0029] Table 3 Layered excavation characteristics of Shuangjiangkou main transformer room

[0030] Table 4 Layered excavation characteristics of Shuangjiangkou tailwater chamber

[0031] Table 5 Layered excavation characteristics of tailwater tunnel section behind tailwater chamber

[0032] Table 6 Layered excavation characteristics of tailwater connection pipe section before tailwater lock chamber

[0033] S2. Measure and analyze the surrounding rock parameters of rock samples in the target area of ​​the underground powerhouse, including the in-situ stress environment, lithology of the surrounding rock, and strength parameters of the surrounding rock. In this embodiment, system anchor rods and prestressed anchor cables are obtained. The role of the system anchor rods is mainly reflected in participating in the coordinated deformation process of the surrounding rock. The elastic recovery deformation of the system anchor rods has a reverse locking force, which forms an anchoring effect on the surrounding rock. Further, the deformation and strength parameters of the anchored rock mass can be improved.

[0034] Then the shear strength parameter of the surrounding rock after the system anchor is applied is determined by the following formula:

[0035] Based on formula (1), the cohesion increment of the surrounding rock after the system anchor is applied is Determined by the following formula:

[0036] in, To increase the cohesion of the surrounding rock before anchoring, is the internal friction angle of the surrounding rock before anchoring; is the shear strength of the anchor rod, is the cross-sectional area of ​​the anchor rod, is the vertical and horizontal spacing of anchor rods, and the group anchor effect coefficient is the dimensionless coefficient, is the anchor diameter, group anchor effect coefficient With system anchor diameter Related to factors such as; Group anchor effect coefficient The general value range is 2.0 to 5.0.

[0037] It should be noted that in the traditional anchor reinforcement mechanism, the reinforcement function of the anchor cable is: (1) Suspension to prevent the separated rock blocks from falling off; (2) Re-bonding the damaged rock mass to make it more integrated, thereby improving the overall strength.

[0038] In this embodiment, Figure 2 As shown in the figure, the prestressed anchoring measures not only have the above-mentioned effects, but also exert positive pressure on the rock mass along the anchoring direction, which is equivalent to increasing the lateral confining pressure of the surrounding rock, so that the rock mass near the excavation surface, which was originally in a uniaxial stress state, is put into a triaxial stress state again, thereby improving the strength of the surrounding rock; A point on the free surface of the cave wall is under unidirectional pressure, that is, , , corresponding to the Moore circle in the figure , and after the prestress is applied, the confining pressure of the cave wall increases, which reduces the radius of the Mohr circle, resulting in the stress tangent point changing from Down to , corresponding to the shear stress Axis Intercept Difference , the intercept is the cohesion increment of the surrounding rock provided by the anchor cable .

[0039] Assuming that the rock friction coefficient before and after reinforcement unchanged, by Figure 2 It can be inferred that when the prestress N (KN) is applied and the spacing between the anchor cables is a × b (m), the cohesion increment of the surrounding rock after the prestressed anchor cables are applied is Determined by the following formula:

[0040] Among them, the group anchor effect coefficient The value range is 2.0~5.0, is the internal friction angle of the surrounding rock before anchoring.

[0041] S3. Determine the support strength by calculating the cohesion increment of the surrounding rock; The support strength is determined by the regression fitting relationship between the system anchor rod, prestressed anchor cable and surrounding rock strength stress ratio and the excavation span of the powerhouse, and a regression fitting model is established through the regression fitting relationship.

[0042] Determine the support strength: According to the lithology, strength and ground stress environment of the surrounding rock, combined with the above-mentioned regression fitting relationship, determine the reasonable support strength of the system anchor and prestressed anchor cable.

[0043] System anchors: System anchors are used on the side walls of underground powerhouses to improve the shear strength parameters of the surrounding rock. The role of the anchor is reflected in the coordinated deformation process of the surrounding rock. The elastic recovery deformation of the anchor forms a reverse locking force, which produces an anchoring effect on the surrounding rock.

[0044] Prestressed anchor cables: Prestressed anchor cables are used for reinforcement at key locations. By applying positive pressure to the surrounding rock along the anchoring direction, the lateral confining pressure of the surrounding rock is increased, thereby increasing the overall cohesion increment of the surrounding rock.

[0045] In this embodiment, the cohesion increment of the surrounding rock under the action of the system anchor is calculated, as shown in Table 7 below, and the physical and mechanical parameters of the surrounding rock, the maximum ground stress value, and the anchor support parameters of the underground powerhouses of 20 large domestic hydropower stations such as Jiangkou, Shuibuya, and Yele are collected.

[0046] Table 7 Relevant data of each plant and the incremental value of surrounding rock cohesion of anchor support

[0047] Among them, the maximum principal stress of the ground stress is taken as the maximum principal stress value near the main power building, and according to the design principle of "arch and wall are different", the system anchor rods on the side walls of the main power building are used for statistics in the statistical data.

[0048] For the upstream and downstream side wall systems with changes in anchor rod arrangement, the average value is taken for statistics.

[0049] In one practicable manner, the incremental cohesion of the surrounding rock under the action of the system anchor is calculated Strength-stress ratio The relationship between the surrounding rock cohesion increment From the above formula (2), we get The value is 3.5. The value is 200MPa, and the strength-stress ratio is a dimensionless constant.

[0050] Based on the surrounding rock strength stress ratio of 20 underground powerhouses in Table 7 Increment of surrounding rock cohesion , to obtain 20 data points, and make a curve fit based on the 20 data points, such as Figure 3 As shown, the system anchor support strength can be obtained The formula is as follows:

[0051] from Figure 3 It can be concluded that 20 data points are distributed above and below the fitting curve to form a data band around the curve at a certain distance above and below the curve, and the surrounding rock cohesion increment With the strength stress ratio The formula (4) is the empirical fitting result based on the existing data and is used to predict the change of surrounding rock cohesion increment under different conditions.

[0052] Specifically, if Figure 3 The changing trend of the middle curve shows that: When the strength stress When , the support strength reflected by the increment of surrounding rock cohesion gradually approaches a constant value; When the strength stress ratio The curve gradually rises, indicating that as the strength-stress ratio of the surrounding rock decreases, the required support strength increases significantly; When the strength stress ratio The surrounding rock of the underground powerhouse is in a high to extremely high ground stress state, and the required support strength increases rapidly. It shows -2 order singularity with the strength stress ratio.

[0053] Based on formula (4), it can be shown that the smaller the surrounding rock strength of the underground powerhouse and the higher the ground stress, the greater the required support strength. However, the growth rate and the strength-stress ratio show a nonlinear relationship, which can be expressed by the following formula:

[0054] In another possible implementation, the incremental cohesion of the surrounding rock under the action of the system anchor is calculated Strength-stress ratio And the excavation span of the plant The relationship between the surrounding rock cohesion increments of the 20 underground powerhouses in Table 7 is Excavation span of the plant , strength stress ratio , get three columns of data points, and make a surface fitting based on the three columns of data points, then the system anchor support strength Determined by the following formula:

[0055] Specifically, if Figure 4 As shown, the cohesion increment of surrounding rock is Excavation span of the plant It is approximately a linear relationship, and as the excavation span of the plant increases Compared with formula (6), the strength stress ratio When the system anchor support strength Strength-stress ratio It still shows -2 singularity, which can be expressed as: .

[0056] In another embodiment, the cohesion increment of the surrounding rock under the action of prestressed anchor cables is calculated, as shown in Table 8 below, including anchor cable support parameters for underground powerhouses of 12 large and medium-sized domestic hydropower stations.

[0057] Table 8 Relevant data of each plant and the cohesion increment value of surrounding rock supported by anchor cables

[0058] In one feasible approach, the cohesion increment of the surrounding rock under the action of prestressed anchor cables is calculated. Strength-stress ratio The relationship between the surrounding rock cohesion increment From the above formula (3), we get The value is 3.5.

[0059] Based on the surrounding rock strength stress ratio of the 12 underground powerhouses in Table 8 Increment of surrounding rock cohesion , to obtain 12 data points, and make a curve fit based on the 12 data points, such as Figure 5 As shown, the prestressed anchor cable support strength can be obtained The formula is as follows:.

[0060]

[0061] Specifically, if Figure 5 As shown in Figure 2, the cohesion increment of the surrounding rock provided by the prestressed anchor cable is It decreases with the increase of strength-stress ratio, and the trend of the curve shows that: When the strength stress When , the speed of support strength reduction gradually slows down, and the support strength eventually approaches zero; When the strength stress ratio The growth rate of support strength is accelerated.

[0062] Furthermore, Figure 5 The changing trend of the middle curve can be determined by the following formula:

[0063] Among them, Figure 5 and Figure 3 By comparison, the fitting curves of system anchors and prestressed anchor cables have the following differences: First, the fitting curve of the anchor cable has no obvious transition zone; Second, when The upward trend of the anchor cable fitting curve is smaller than that of the anchor rod fitting curve; Third, when The cable fitting curve does not gradually approach a constant like the bolt fitting curve, but still gradually decreases at a certain rate. These differences show that: the cable provides greater support strength than the bolt; Fourth, when The rate at which the cable anchor strength changes with the strength-stress ratio is lower than that of the bolt.

[0064] In another feasible way, the increment of surrounding rock cohesion under the action of prestressed anchor cables is calculated. Strength-stress ratio And the excavation span of the plant The relationship between the surrounding rock cohesion increments of the 12 underground powerhouses in Table 8 is Excavation span of the plant , strength stress ratio , get three columns of data points, and make a surface fitting based on the three columns of data points, then the strength of the prestressed anchor cable support is Determined by the following formula:

[0065] Specifically, if Figure 6 As shown, 12 data points are distributed above and below the fitting curve, among which the cohesion increment As the factory building excavation span increases with the increase of When the surrounding rock cohesion increment is greater than a certain value Excavation span of the plant Approximately linear relationship.

[0066] S4. Define dimensionless system anchor support index based on regression fitting relationship and prestressed anchor support index , which is used to reflect the relative relationship between the actual support strength and the empirical formula.

[0067] In this embodiment, in order to better reflect the relative relationship between the actual support strength and the empirical formula, a dimensionless support index is proposed; Defining the dimensionless system bolting index Determined by the following formula:

[0068] In formula (10), the numerator is the calculated value of the support strength of the system anchor based on formula (2), and the denominator is the support strength calculated based on the empirical fitting formula (4) or (6).

[0069] Similarly, the dimensionless prestressed anchor cable support index is defined as Determined by the following formula:

[0070] The numerator is the calculated value of the support strength of the prestressed anchor cable based on formula (3), and the denominator is the support strength calculated based on the empirical fitting formula (7) or (9).

[0071] In the preferred solution, as shown in Table 9 below, the system anchor support index I of each project can be calculated using formula (10): b ; Table 9 Anchor support index of underground workshops

[0072] Specifically, if Figure 7 As shown: First, the system anchor support index Most of them are distributed around 1.0, and the farther away from 1.0, the fewer points there are; Second, the support index calculated by different fitting formulas for the same project is similar; It is shown that the empirical formula can well reflect the anchor support strength of the system, and the fitting values ​​of empirical formula (4) and empirical formula (6) are similar.

[0073] In the preferred solution, as shown in Table 10 below, the anchor support index I of each project can be calculated using formula (11): p ; Table 10 Anchor support index of underground workshops

[0074] Specifically, by Figure 8 As shown: First, the prestressed anchor support index Distributed around 1.0; Second, the support indexes calculated using different fitting formulas for the same project are similar.

[0075] It is shown that the empirical formula can reflect the strength of anchor cable support, and the fitting values ​​of empirical formulas (7) and (9) are similar.

[0076] In summary, combining engineering practice with empirical formulas, the support index can be used as a reference for actual engineering support design. The evaluation criteria are as follows:

[0077] Based on the statistical analysis of the surrounding rock parameters and support design data of 20 domestic hydropower stations including Jiangkou, Shuibuya, and Yele in the above tables, the following conclusions can be drawn: First, system anchors or prestressed anchor cables can provide additional cohesion increments to the surrounding rock.

[0078] Among them, the cohesion increment reflects the support strength and strength stress ratio , Plant excavation span It shows a certain functional relationship, and calculates the strength and strength-stress ratio of the system anchor and prestressed anchor cable support through the statistical method of least squares fitting. , Excavation span 4 empirical formulas.

[0079] Second, in the system anchor support, when the strength stress ratio When the underground powerhouse surrounding rock is in a high to extremely high ground stress state, the required support strength increases rapidly; In prestressed anchor cable support, when the strength stress ratio The required support strength increases significantly.

[0080] Third, the dimensionless support index is determined based on the empirical fitting formula. The support index can be used to intuitively characterize the relative relationship between the design support strength and the engineering experience support strength.

[0081] Among them, the support index can be used as a quantitative evaluation standard for support strength to guide the design of system anchors and prestressed anchor cables.

[0082] In combination with the above further description, the present invention also includes one or more processors and a machine-readable storage medium, in which the storage medium stores machine-executable instructions that can be executed by the processor. The processor reads and executes these instructions to implement the underground plant excavation and support construction method.

[0083] The processor may include one or more processing units, for example, the processor may include an application processor (AP), a modem processor, a graphics processor (GPU), an image signal processor (ISP), a controller, a memory, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural-network processing unit (NPU), etc. Among them, different processing units may be independent devices or integrated into one or more processors. Among them, the controller may be a nerve center and a command center. The controller may generate an operation control signal according to the instruction opcode and the timing signal to complete the control of fetching and executing instructions. A memory may also be provided in the processor for storing instructions and data. In some embodiments, the memory in the processor is a high-speed cache memory. The memory may store instructions or data that have just been used or circulated by the processor. If the processor needs to use the instruction or data again, it may be directly called from the memory. Repeated access is avoided, the waiting time of the processor is reduced, and the efficiency of the system is improved.

[0084] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)), etc.

[0085] The various illustrative logic units and circuits described in the embodiments of the present application can be implemented or operated by a general-purpose processor, a digital signal processor, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination of the above. The general-purpose processor can be a microprocessor, and optionally, the general-purpose processor can also be any conventional processor, controller, microcontroller or state machine. The processor can also be implemented by a combination of computing devices, such as a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a digital signal processor core, or any other similar configuration.

[0086] The steps of the method or algorithm described in the embodiments of the present application can be directly embedded in the software unit executed by the hardware, the processor, or a combination of the two. The software unit can be stored in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM or other storage media of any form in the art. Exemplarily, the storage medium can be connected to the processor so that the processor can read information from the storage medium and can write information to the storage medium. Alternatively, the storage medium can also be integrated into the processor. The processor and the storage medium can be arranged in an ASIC.

[0087] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0088] Although the present application has been described in conjunction with specific features and embodiments thereof, it is obvious that various modifications and combinations may be made thereto without departing from the spirit and scope of the present application. Accordingly, this specification and the drawings are merely exemplary illustrations of the present application as defined by the appended claims, and are deemed to have covered any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, a person skilled in the art may make various modifications and variations to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

[0089] It should also be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so as to describe the embodiments of the present invention described herein.

Claims

1. A construction method for excavation and support of underground powerhouse, characterized in that: The following steps are involved: S1. Measure and analyze the surrounding rock parameters of rock samples in the target area of ​​the underground powerhouse, including the in-situ stress environment, lithology of the surrounding rock and strength parameters of the surrounding rock; S2. Determine the support strength based on surrounding rock parameters; Among them, the support strength is determined by the regression fitting relationship between the system anchor, prestressed anchor cable and surrounding rock strength stress ratio and the powerhouse excavation span, and a regression fitting model is established through the regression fitting relationship; S3. Define the dimensionless system anchor support index and prestressed anchor support index , which is used to reflect the relative relationship between the actual support strength and the empirical formula.

2. The underground powerhouse excavation support construction method according to claim 1 is characterized in that: In step S1, according to the local stress environment, the lithology of the surrounding rock and the strength parameters of the surrounding rock, the reverse locking force formed by the elastic recovery deformation of the system anchor rod on the surrounding rock is determined, and the support effect of the system anchor rod is reflected by adjusting the shear strength parameters of the surrounding rock; Then the shear strength parameter of the surrounding rock after the system anchor is applied is determined by the following formula: Based on formula (1), the cohesion increment of the surrounding rock after the system anchor is applied is Determined by the following formula: in, To increase the cohesion of the surrounding rock before anchoring, is the internal friction angle of the surrounding rock before anchoring; is the shear strength of the anchor rod, is the cross-sectional area of ​​the anchor rod, is the vertical and horizontal spacing of anchor rods, and the group anchor effect coefficient is the dimensionless coefficient, is the anchor diameter; Group anchor effect coefficient The value range is 2.0~5.

0.

3. The underground powerhouse excavation support construction method according to claim 2 is characterized in that: In step S2, the prestressed anchor cable applies prestress to the surrounding rock to increase the confining pressure of the cave wall, corresponding to the shear stress The intercept difference is the increment of surrounding rock cohesion provided by the anchor cable. , the rock friction coefficient before and after reinforcement When the prestress N is applied and the spacing is a×b, the cohesion increment of the surrounding rock after the prestressed anchor cable is applied is Determined by the following formula: in, is the internal friction angle of the surrounding rock before anchoring.

4. The underground powerhouse excavation support construction method according to claim 3 is characterized in that: In step S2, the cohesion increment of the surrounding rock under the action of the system anchor is calculated based on formula (2): , the cohesion increment of the surrounding rock under the action of the system anchor Strength-stress ratio The relationship between is obtained by curve fitting and the value is =3.5, =200MPa, then the system anchor support strength Determined by the following formula: Among them, the strength stress ratio is a dimensionless constant.

5. The underground powerhouse excavation support construction method according to claim 4 is characterized in that: Based on formula (4), it can be concluded that, under the premise of satisfying the stability of the surrounding rock, the decrease of surrounding rock strength and the increase of ground stress will increase the support strength accordingly, and its growth rate is proportional to the strength-stress ratio. The relationship between is nonlinear and is determined by the following formula: 。 6. The underground powerhouse excavation support construction method according to claim 4 is characterized in that: Cohesion increment of surrounding rock under the action of system anchor Strength-stress ratio And the excavation span of the plant The relationship between is obtained by surface fitting, then the system anchor support strength Determined by the following formula: Among them, the cohesion increment of surrounding rock is Excavation span of the plant It is approximately linear and changes with the excavation span of the plant. The increase of strength stress ratio increases based on formula (6). When the system anchor support strength Strength-stress ratio The -2 singularity is expressed as: .

7. The underground powerhouse excavation support construction method according to claim 6 is characterized in that: In step S2, the cohesion increment of the surrounding rock under the action of the prestressed anchor cable is calculated based on formula (3): , the cohesion increment of surrounding rock under the action of prestressed anchor cables Strength-stress ratio The relationship between is obtained by curve fitting and the value is =3.5, then the strength of prestressed anchor cable support Determined by the following formula: 。 8. The underground powerhouse excavation support construction method according to claim 7 is characterized in that: Based on formula (7), it can be concluded that the strength of prestressed anchor cable support is Strength-stress ratio decreases with the increase of and is determined by the following formula: 。 9. The underground powerhouse excavation support construction method according to claim 7, characterized in that: Cohesion increment of surrounding rock under the action of prestressed anchor cables Strength-stress ratio And the excavation span of the plant The relationship between is obtained by surface fitting, then the strength of prestressed anchor cable support is Determined by the following formula: Among them, the cohesion increment of surrounding rock under the action of prestressed anchor cable is Excavation span of the factory building increases with the increase of When it is greater than a certain value, the cohesion increment of the surrounding rock under the action of the prestressed anchor cable Excavation span of the plant Approximately linear relationship.

10. The underground powerhouse excavation support construction method according to claim 9, characterized in that: In step S3, in order to reflect the relative relationship between the actual support strength and the empirical formula, a dimensionless support index is proposed; Defining the dimensionless system bolting index Determined by the following formula: Wherein, the numerator is the calculated value of the support strength of the system anchor based on formula (2), and the denominator is the support strength calculated based on the empirical fitting formula (4) or (6); Definition of dimensionless prestressed anchor cable support index Determined by the following formula: The numerator is the calculated value of the support strength of the prestressed anchor cable based on formula (3), and the denominator is the support strength calculated based on the empirical fitting formula (7) or (9).

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