CN113886919B - Ultra-large-span underground cavern support design determination method based on energy field balance - Google Patents
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Abstract
The invention relates to an ultra-large span underground cavern support design determination method based on energy field balance, which comprises the following steps: (1) The method comprises the steps of obtaining energy values when unit rock mass is loaded to damage in a huge-span cavity body range through a site loading test; (2) Calculating stress and strain fields of the giant-span cavity under the working condition of full section excavation without support, and determining an unstable area in the cavity; (3) Respectively calculating stress and strain fields of the cavern under different excavation schemes, and comparing and selecting an excavation scheme with the minimum area of an unstable region as an optimal excavation scheme; (4) On the basis of an optimal excavation scheme, calculating stress and strain fields of the grotto under the working condition of taking supporting measures; the supporting measures are continuously adjusted and optimized, so that the supporting measures with the area of the unstable energy area being zero are used as a final supporting scheme of the ultra-large-span underground cavern. The invention takes the energy as the index for judging the stability of the rock mass, accords with the material destruction characteristic and the stability mechanism, and has reasonable and reliable design method.
Description
Technical Field
The invention relates to the field of tunnel underground engineering design and construction, in particular to an ultra-large span underground cavity optimal supporting scheme determination method based on energy field balance.
Background
For underground engineering of tunnel caverns, qualitative and quantitative methods are often adopted for design and construction, engineering analogy methods are generally adopted for qualitative and quantitative methods such as stratum-structure and load-structure are generally adopted for quantitative; for ultra-large spans, particularly underground caverns with spans larger than 40m, engineering analogy methods cannot be used as design basis due to few engineering cases, and stratum-structure methods in quantitative analysis methods are difficult to judge in terms of damage basis and damage forms, and loads in load-structure methods depend on empirical formulas, so that the method is not applicable to such span underground caverns.
In summary, most of the existing design methods are empirical formulas, and the stability of the rock mass is judged by two mutually independent indexes of strength and deformation, so that the method is suitable for a conventional grotto, but has certain limitations for ultra-large span underground grotto because the ultra-large span underground grotto cannot provide definite load and has no reliable damage index.
Disclosure of Invention
Based on the limitations of the conventional design method applied to the huge span grotto support design, the invention provides a method for designing an oversized span underground grotto by taking an energy field formed by combining stress and strain as an evaluation index.
The invention solves the technical problems by adopting the technical scheme that: the ultra-large-span underground cavern support design determination method based on energy field balance specifically comprises the following steps:
s1, determining the maximum main stress sigma 1 and the minimum main stress sigma 3 of the planned ultra-large-span underground cavity in a field measurement mode;
s2, obtaining rock mass test blocks of the opening area, the middle part and the tail part of the underground cavity to be built in an ultra-large span mode in a drilling mode; carrying out a uniaxial loading compression test and a triaxial loading compression test under the surrounding pressure of the maximum main stress sigma 1 and the minimum main stress sigma 3 on a rock mass test block; calculating to obtain the energy value of a single rock test block when the single rock test block is loaded to a damaged state in the ultra-large-span underground cavity;
S3, establishing a three-dimensional calculation model of the oversized span underground cavity in the steps S1 and S2 by using a computer, calculating stress and strain fields of the oversized span underground cavity under full-section excavation and no supporting working condition, determining rock mass energy values of all units of the cavity, comparing the rock mass energy values of all units of the cavity with the energy values of the rock mass test block determined in the step S2 when the rock mass test block is loaded to a damaged state, and determining an unstable area S in the oversized span underground cavity;
S4, planning an excavation scheme of the oversized underground cavern, determining an unstable area S in each excavation scheme according to the method in the step S3, and taking the excavation scheme with the minimum area of the unstable area S as an optimal excavation scheme; wherein the excavation of the planned oversized underground cavern comprises the following steps: a reserved rock column method, a step method and a pilot tunnel expanding and digging method.
S5, applying supporting measures to the oversized underground cavity under the excavation scheme obtained by screening in the step S4, calculating cavity stress and strain values after supporting according to the calculation method in the step S3, and determining an unstable area S of the cavity;
And S6, adjusting and optimizing the supporting measures until the unstable area S of the cavity is zero, and taking the supporting measures at the moment as a final supporting design scheme for building the ultra-large span underground cavity.
Further, in step S1: and determining the maximum main stress sigma 1 and the minimum main stress sigma 3 of the planned oversized underground cavity by adopting a hydraulic fracturing ground stress method.
Further, the step S2 specifically includes: respectively selecting at least three groups of rock mass test blocks in the hole opening area, the middle part and the tail part of the ultra-large-span underground cavity, wherein the number of the test blocks in each group of rock mass test blocks is more than or equal to 3; respectively carrying out a single-axis loading compression test and triaxial loading compression tests of confining pressures sigma 1 and sigma 3 on each group of rock mass test blocks; the energy values of all rock mass test blocks under the three loading working conditions are obtained, and the calculation formula is as follows:
Wherein: e i is the energy value of each rock mass test block obtained by calculation in the triaxial loading compression experiment of the confining pressure maximum main stress sigma 1 when the rock mass test block is loaded to be destroyed; e j is the energy value of each rock mass test block obtained by calculation in the triaxial loading compression experiment of the confining pressure minimum main stress sigma 3 when the rock mass test block is loaded to be destroyed; e k is the energy value of each rock mass test block obtained by calculation when being loaded to be destroyed in the uniaxial compression test;
Specifically, in the above formula: delta is a stress value in the loading process of the rock mass test block, epsilon is a strain value in the loading process of the rock mass test block, the longitudinal direction is parallel to the loading direction, the transverse direction is perpendicular to the loading direction, delta v、δh is longitudinal and transverse stress values in the loading process of the rock mass test block, epsilon v、εh is longitudinal and transverse strain values in the loading process of the rock mass test block, epsilon v max is a strain value corresponding to delta v max in a longitudinal delta-epsilon curve of the rock mass test block, delta v max is a maximum stress value in a longitudinal delta-epsilon curve of the rock mass test block, epsilon h max is a transverse strain value of the test block when the test block is longitudinally loaded to delta v max, and n is the number of the rock mass test blocks under 3 loading working conditions;
respectively calculating the energy average value under three loading working conditions, Take its minimum valueAs the energy value at which a single rock mass test block is loaded to failure for an oversized underground cavern.
Further, in step S2, the rock mass test blocks are cylindrical test blocks with diameters and heights of 100 mm.
Further, in step S3, the calculation model unit of the oversized underground cavity adopts tetrahedrons, the side lengths are all 1m, and the rock mass energy value of each unit is calculated by drawing delta-epsilon curves of each unit in the x, y and z directions, and the following calculation formulas are adopted:
Wherein: epsilon 1x、ε1y、ε1z is a strain value corresponding to delta 1x、δ1y、δ1z of the oversized underground cavity, and delta 1x、δ1y、δ1z is an initial stress value of the oversized underground cavity in x, y and z directions; epsilon 2x、ε2y、ε2z is a strain value corresponding to delta 2x、δ2y、δ2z of the oversized cavity, delta 2x、δ2y、δ2z is a maximum stress value of the rock mass test block in the x, y and z directions in a delta-epsilon curve, delta x、δy、δz is stress of the cavity in the x, y and z directions, and epsilon x、εy、εz is strain of the cavity in the x, y and z directions;
The cell region with energy E > 0.5E d is defined as the unstable region S; e d is the energy value at which an individual rock mass test block is loaded to failure across an oversized underground cavern.
Further, the span of the ultra-large span underground cavern is more than or equal to 40m.
Preferably, in step S3, the rock mass energy value of each unit of the oversized underground cavern is the rock mass energy value near the dome, shoulder or foot region of the cavern.
Further, in step S6, the optimizing the supporting measure includes: on the basis of the original supporting measures, the anchoring force of the prestressed anchor cable is increased, the anchor rod is lengthened, the thickness of the sprayed concrete is thickened or an arch frame is erected.
Compared with the prior art, the invention has the following advantages and effects:
1. according to the ultra-large span underground cavern support design determination method based on energy field balance, a rock mass test block in the range of a to-be-built ultra-large span underground cavern body is subjected to field loading compression experiments, the energy value when a single rock mass test block is loaded to a damage state is determined, the energy value is used as an index for judging rock mass stability, the material damage characteristic and the stability mechanism are met, and a support scheme determined based on the energy index is particularly suitable for a huge span underground cavern.
2. According to the method, the excavation scheme is screened firstly, the excavation scheme with the least energy unstable region S is used as the optimal excavation scheme, and a theoretical basis is provided for the selection of the existing excavation scheme of the ultra-large span underground cavern.
3. According to the ultra-large span underground cavern support design determination method based on energy field balance, on the basis of the optimal excavation scheme obtained through screening, preliminary support measures are applied, an unstable region S of a planned cavern is calculated, support measures are gradually enhanced until the unstable region S of the cavern is zero, support of the unstable region of the cavern is continuously enhanced aiming at the weak region of the cavern, the cavern gradually reaches a reliable stable state, and the finally obtained support scheme has the advantages of being strong in support stability, reasonable and reliable.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained according to these drawings without inventive faculty for a person skilled in the art.
Fig. 1 is a longitudinal delta-epsilon curve obtained in the triaxial loading compression test of maximum principal stress sigma 1 of confining pressure of a rock mass block in step S2 of the embodiment of the invention.
Fig. 2 is a transverse delta-epsilon curve obtained in the triaxial loading compression test of maximum confining pressure main stress sigma 1 of a rock mass block in step S2 of the embodiment of the present invention.
Fig. 3 is a stress field cloud image (a) and a strain field cloud image (b) of the full section excavation of the ultra-large span underground cavity and under the working condition without support in step S3 according to the embodiment of the present invention.
Fig. 4 is a stress cloud chart of the ultra-large span underground cavity full section excavation and the X direction (fig. a), the Y direction (fig. b) and the Z direction (fig. c) under the non-supporting working condition in step S3 according to the embodiment of the present invention.
Fig. 5 is a schematic diagram of an energy unstable region S (block portion) under the working condition of no support and full section excavation of an oversized underground cavity in step S3 according to an embodiment of the present invention.
FIG. 6 is a conventional step-by-step excavation scheme (sequence numbers represent excavation steps) of an oversized underground cavity in an embodiment of the invention, and A is a reserved middle column method; b is a step method; and C, a pilot tunnel expanding and excavating method.
Fig. 7 is a schematic diagram of the unstable region S of the cavern under the working condition of the primary support in the reserved middle column construction.
Fig. 8 is a schematic diagram of an oversized underground cavern support structure when the column-wise unstable region S in reservation is zero.
Detailed Description
The present invention will be described in further detail with reference to the following examples, which are illustrative of the present invention and are not intended to limit the present invention thereto.
Example 1: as shown in fig. 1 to 8, a method for determining an ultra-large span underground cavern support design based on energy field balance comprises the following steps:
S1, acquiring a maximum main stress sigma 1 and a minimum main stress sigma 3 of a planned 50-meter oversized-span underground cavity field region by adopting a hydraulic fracturing ground stress measurement method;
Wherein: σ 1＝6.2Mpa;σ3 =1.72 Mpa;
S2, obtaining rock mass test blocks of an opening, a middle part and a tail part of a planned oversized underground cavity in a drilling mode, carrying out a single-shaft loading compression experiment and a field loading compression experiment under a maximum main stress sigma 1 and a minimum main stress sigma 3, and obtaining the energy value when a single rock mass test block is loaded to a damaged state in the oversized underground cavity through calculation;
The specific scheme is as follows: 10 groups of rock mass test blocks within the range of the ultra-large span underground cavern body are selected; wherein: 3 groups are taken at the hole opening, 4 groups are taken at the middle part of the hole, 3 groups are taken at the tail part of the hole, and 3 rock mass test blocks are taken in each group; performing triaxial loading compression experiments of confining pressure sigma 1 =6.2 Mpa, triaxial loading compression experiments of confining pressure sigma 3 =1.72 Mpa and uniaxial loading compression experiments on rock mass test blocks of each group respectively; the energy value of each rock mass test block in each group when being loaded to a damage state under the three loading working conditions is calculated, and the calculation formula is as follows:
in the above formula: e i is the energy value of each group of rock mass test blocks obtained by calculation in the triaxial loading compression experiment with the confining pressure of 6.2Mpa maximum principal stress when the rock mass test blocks are loaded to be destroyed; e j is the energy value of each group of rock mass test blocks obtained by calculation in the triaxial loading compression experiment with the minimum confining pressure main stress of 1.72Mpa when the rock mass test blocks are loaded to be destroyed; e k is the energy value of each group of rock mass test blocks obtained by calculation in the uniaxial compression test when the rock mass test blocks are loaded to be destroyed; delta is a stress value in the loading process of the rock mass test block, epsilon is a strain value in the loading process of the rock mass test block, the longitudinal direction is parallel to the loading direction, the transverse direction is perpendicular to the loading direction, delta v、δh is longitudinal and transverse stress values in the loading process of the rock mass test block, epsilon v、εh is a longitudinal and transverse strain value in the loading process of the rock mass test block, epsilon v max is a strain value corresponding to delta v max in a longitudinal delta-epsilon curve of the rock mass test block, delta v max is a maximum stress value in a longitudinal delta-epsilon curve of the rock mass test block, and epsilon h max is a transverse strain value of the test block when the rock mass test block is longitudinally loaded to delta v max;
E i calculation example: taking a first test block of a first group of test blocks of the hole section, carrying out a confining pressure sigma 1 =6.2 Mpa triaxial loading compression test to obtain a longitudinal delta-epsilon curve and a transverse delta-epsilon curve of the test block, obtaining delta v max＝22.3Mpa;εvmax＝0.011,εh max=0.018 by using graphs shown in fig. 1 and 2, and calculating to obtain an energy value of the test block: the remaining test blocks can be calculated as follows:
Ei＝(279，290，301...269)(i＝1，2，3..30)；
the triaxial loading compression experiment calculation results of the minimum confining pressure main stress of 1.72Mpa of each group of rock mass test blocks are as follows:
Ej＝(186，193，201...176)(j＝1，2，3..30)；
In the uniaxial compression test, the calculated energy values of each group of rock mass test blocks when loaded to damage:
Ek＝(135，169，211...173)(k＝1，2，3..30)；
E j、Ek can be obtained by respectively drawing a longitudinal delta-epsilon curve and a transverse delta-epsilon curve of a triaxial loading compression test with the minimum principal stress of 1.72Mpa and a longitudinal delta-epsilon curve of a uniaxial compression test, and referring to an E i calculation example;
Respectively calculating energy average values under three loading working conditions:
take its minimum value The value is the energy value when the oversized cross-cavity rock mass test block is loaded to a damaged state, and the units of energy are kj.
S3, establishing the steps S1 and S2 by adopting computer software (for example MIDAS/GTS NX or FLAC 3D), wherein a three-dimensional calculation model unit of the oversized underground cavity adopts tetrahedrons, the side length is 1m, the calculation parameters select geological parameters in a geological survey report, stress and strain fields of the oversized underground cavity under the working condition of full section excavation and no support are calculated, rock mass energy values of all units of the cavity are determined, and the rock mass energy values of all units of the cavity are compared with the energy values of rock mass test blocks determined in the step S2 when the rock mass test blocks are loaded to a damaged state, so that an unstable area S in the oversized underground cavity is determined;
Specifically, the total stress field cloud diagram of the ultra-large span underground cavity full section excavation under the working condition without support is shown in fig. 3 (a), and the total stress field cloud diagram is shown in fig. 3 (b). Drawing delta-epsilon curves of all units (a vault A, a vault B or rock mass units near a vault area) of the cavern in the X, Y and Z directions, and calculating energy values of all the units by using stress cloud charts in the X, Y and Z directions as shown in fig. 4:
In the formula, epsilon 1x、ε1y、ε1z is a strain value corresponding to the ultra-large span cavity in delta 1x、δ1y、δ1z, and delta 1x、δ1y、δ1z is an initial stress value of the ultra-large span underground cavity in x, y and z directions; epsilon 2x、ε2y、ε2z is a strain value corresponding to the ultra-large cross chamber in delta 2x、δ2y、δ2z, delta 2x、δ2y、δ2z is a maximum stress value of the rock mass test block in the x, y and z directions in a delta-epsilon curve, delta x、δy、δz is stress of the chamber in the x, y and z directions, and epsilon x、εy、εz is strain of the chamber in the x, y and z directions. The cell region with energy E > 0.5E d is defined as the unstable region S; if E A＜0.5Ed＝99;EB＞0.5Ed =99, the unit B belongs to the unstable region S, and the other units can respectively calculate and determine whether the unit B belongs to the unstable region S by using the method, so as to obtain the unstable region S under the working condition of full-section excavation of the ultra-large-span underground cavity and no support, as shown in a square frame part in fig. 5.
S4, planning an excavation scheme of the oversized underground cavern, determining an unstable area S in each excavation scheme according to the method in the step S3, and taking the excavation scheme with the minimum area of the unstable area S as an optimal excavation scheme;
Specifically, as shown in fig. 6, the conventional excavation scheme includes a reserved middle column method, a three-step method and a pilot tunnel expanding excavation method, stress and strain values of chambers under the 3 excavation schemes are calculated respectively, an unstable region S in each excavation scheme is obtained according to the calculation method in the step (3), and the area of the unstable region S obtained by the reserved middle rock column method is smaller than that obtained by the selected method, namely the reserved middle column method is the optimal excavation scheme.
S5, applying a preliminary supporting measure to the oversized underground cavity under the optimal excavation scheme obtained by screening in the step S4, calculating the stress and the strain value of the cavity after supporting according to the calculation method in the step S3, and determining an unstable area S of the cavity;
Specifically, the preliminary supporting measures can be that the length of the construction prestressed anchor cable is L=15m@7m, the anchoring force is F=500 kN, the anchor rod is L=3m@7m, and the sprayed concrete thickness is h=10cm; according to the calculation method of the step S3, an unstable area S under the supporting working condition of the grotto is obtained, and the area of the unstable area S is smaller than that of the whole-section excavation and the working condition without the supporting working condition, as shown in a block part of a figure 7;
And S6, adjusting and optimizing the supporting measures until the unstable area S of the cavity is zero, and taking the supporting measures at the moment as a final supporting scheme for building the ultra-large span underground cavity.
Specifically, on the basis of the preliminary support in the step, the support measures are gradually enhanced, stress and strain values of the cavern are respectively calculated, and according to the calculation method in the step S3, the support measures for enabling the area of the unstable area S to be zero are finally obtained, and as shown in FIG. 8, the unstable area S disappears; the supporting measure at this time is that the length of the prestressed anchor cable is L=25m@5 m, the anchoring force is F=150kn, the anchor rod is L=6m@5 m, and the sprayed concrete thickness is h=20cm, and the supporting measure can be used as the optimal supporting measure of the oversized underground cavity in the embodiment.
The method for determining the support design of the ultra-large span underground cavern based on energy field balance in the embodiment 1 takes energy as an index for judging rock mass stability, accords with material damage characteristics and a stability mechanism, is reasonable and reliable, can rapidly determine the optimal excavation and support scheme of the ultra-large span underground cavern with the span of more than 40m, and has important theoretical guidance significance for actual tunnel underground engineering design and construction.
In addition, the specific embodiments described in the present specification may differ in terms of parts, shapes of components, names, and the like. All equivalent or simple changes of the structure, characteristics and principle according to the inventive concept are included in the protection scope of the present invention. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions in a similar manner without departing from the scope of the invention as defined in the accompanying claims.
Claims (8)
1. The method for determining the ultra-large span underground cavern support design based on energy field balance is characterized by comprising the following steps of:
s1, determining the maximum main stress sigma 1 and the minimum main stress sigma 3 of the planned oversized underground cavity in a field measurement mode;
S2, obtaining rock mass test blocks of the opening area, the middle part and the tail part of the underground cavity to be built in an ultra-large span mode in a drilling mode; respectively carrying out a uniaxial loading compression test and a triaxial loading compression test under the surrounding pressure of the maximum main stress sigma 1 and the minimum main stress sigma 3 on the rock mass test block; calculating to obtain the energy value of a single rock test block when the single rock test block is loaded to a damaged state in the ultra-large-span underground cavity;
S3, establishing a three-dimensional calculation model of the oversized underground cavity in the steps S1 and S2 by using a computer, calculating stress and strain fields of the oversized underground cavity under full-section excavation and no supporting working condition, determining rock mass energy values of all units of the cavity, comparing the rock mass energy values of all units of the cavity with the energy values of the rock mass test block determined in the step S2 when the rock mass test block is loaded to a damaged state, and determining an unstable region S in the oversized underground cavity;
S4, planning an excavation scheme of the oversized underground cavern, determining an unstable area S in each excavation scheme according to the method in the step S3, and taking the excavation scheme with the minimum area of the unstable area S as an optimal excavation scheme;
s5, applying supporting measures to the oversized underground cavity under the excavation scheme obtained by screening in the step S4, calculating cavity stress and strain values after supporting according to the calculation method in the step S3, and determining an unstable area S of the cavity;
and S6, adjusting and optimizing the supporting measures until the unstable area of the cavity is zero, and taking the supporting measures at the moment as a final supporting design scheme for building the ultra-large span underground cavity.
2. The method for determining the ultra-large-span underground cavern support design based on energy field balance according to claim 1, wherein in step S1: and determining the maximum main stress sigma 1 and the minimum main stress sigma 3 of the planned oversized underground cavity by adopting a hydraulic fracturing ground stress method.
3. The method for determining the ultra-large-span underground cavern support design based on energy field balance according to claim 1, wherein the step S2 is specifically: at least three groups of rock mass test blocks are selected from the opening, the middle part and the tail part of the oversized underground cavity, and the number of the test blocks in each group of rock mass test blocks is more than or equal to 3; respectively carrying out a single-axis loading compression test and triaxial loading compression tests of confining pressures sigma 1 and sigma 3 on rock mass test blocks of each group; the energy values of all rock mass test blocks under the three loading working conditions are obtained, and the calculation formula is as follows:
Wherein: e i is the energy value of each rock mass test block obtained by calculation in the triaxial loading compression experiment of the confining pressure maximum main stress sigma 1 when the rock mass test block is loaded to be destroyed; e j is the energy value of each rock mass test block obtained by calculation in the triaxial loading compression experiment of the confining pressure minimum main stress sigma 3 when the rock mass test block is loaded to be destroyed; e k is the energy value of each rock mass test block obtained by calculation when being loaded to be destroyed in the uniaxial compression test;
Specifically, in the above formula: delta is a stress value in the loading process of the rock mass test block, epsilon is a strain value in the loading process of the rock mass test block, the longitudinal direction is parallel to the loading direction, the transverse direction is perpendicular to the loading direction, delta v、δh is longitudinal and transverse stress values in the loading process of the rock mass test block, epsilon v、εh is longitudinal and transverse strain values in the loading process of the rock mass test block, epsilon v max is a strain value corresponding to delta v max in a longitudinal delta-epsilon curve of the rock mass test block, delta v max is a maximum stress value in a longitudinal delta-epsilon curve of the rock mass test block, epsilon h max is a transverse strain value of the test block when the test block is longitudinally loaded to delta v max, and n is the number of the rock mass test blocks under 3 loading working conditions;
respectively calculating the energy average value under three loading working conditions, Take its minimum value/>As the energy value at which a single rock mass test block is loaded to failure for an oversized underground cavern.
4. The method for determining the ultra-large-span underground cavern support design based on energy field balance according to claim 3, wherein in the step S2, the rock mass test blocks are cylindrical test blocks with the diameter and the height of 100 mm.
5. The method for determining the support design of the oversized underground cavern based on the energy field balance according to claim 3, wherein in the step S3, calculation model units of the oversized underground cavern adopt tetrahedrons, the side lengths are 1m, the rock mass energy values of the units are calculated by drawing delta-epsilon curves of the units in the x, y and z directions, and the following calculation formulas are adopted:
wherein: epsilon 1x、ε1y、ε1z is a strain value corresponding to delta 1x、δ1y、δ1z of the oversized underground cavity, and delta 1x、δ1y、δ1z is an initial stress value of the oversized underground cavity in x, y and z directions; epsilon 2x、ε2y、ε2z is a strain value corresponding to delta 2x、δ2y、δ2z of an oversized underground cavity, delta 2x、δ2y、δ2z is a maximum stress value of a rock mass test block in x, y and z directions in a delta-epsilon curve, delta x、δy、δz is a stress value of the cavity in x, y and z directions, and epsilon x、εy、εz is the strain of the cavity in x, y and z directions;
The cell region with energy E > 0.5E d is defined as the unstable region S; e d is the energy value at which an individual rock mass test block is loaded to failure across an oversized underground cavern.
6. The method for determining the support design of the ultra-large span underground cavern based on energy field balance according to claim 1, wherein the span of the ultra-large span underground cavern is greater than or equal to 40m.
7. The method for determining the support design of the ultra-large-span underground cavern based on the energy field balance according to claim 5, wherein in the step S3, the energy value of each unit rock mass of the ultra-large-span underground cavern is the energy value of the rock mass near the vault, the arch shoulder or the arch foot area of the cavern.
8. The method for determining the support design of the ultra-large-span underground cavern based on the energy field balance according to claim 5, wherein in the step S6, the optimizing the support measure comprises: on the basis of the original supporting measures, the anchoring force of the prestressed anchor cable is increased, the anchor rod is lengthened, the thickness of the sprayed concrete is thickened or an arch frame is erected.
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| CN111502715A (en) * | 2020-05-29 | 2020-08-07 | 中铁第六勘察设计院集团有限公司 | Method for comprehensively constructing fractured rock mass in oversized underground cavern crossing stage |
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| CN111502715A (en) * | 2020-05-29 | 2020-08-07 | 中铁第六勘察设计院集团有限公司 | Method for comprehensively constructing fractured rock mass in oversized underground cavern crossing stage |
| CN111753361A (en) * | 2020-06-29 | 2020-10-09 | 中国人民解放军空军工程大学 | Method for calculating surrounding rock dynamic stability composite criterion under action of explosive load |
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