Pressure relief method for expansive tunnel surrounding rock
阅读说明：本技术 一种膨胀性隧道围岩的卸压方法 (Pressure relief method for expansive tunnel surrounding rock ) 是由 许崇帮 李磊 秦幼林 王华牢 于 2019-11-12 设计创作，主要内容包括：本发明涉及一种膨胀性隧道围岩的处治方法,具体涉及一种膨胀性隧道围岩的卸压方法,所述方法包括如下步骤：(1)探明因隧道施工导致膨胀性围岩的扰动范围；(2)试验确定膨胀性围岩试块的孔隙率n、膨胀率α及抗压强度σ<Sub>ci</Sub>；(3)初步确定膨胀性围岩卸压换填的位置和深度；(4)计算膨胀性围岩的弹性模量E<Sub>m</Sub>及抗压强度σ<Sub>cm</Sub>；(5)选取弹性体换填材料类型；(6)计算确定卸压换填孔的孔径、孔深、孔数及孔距；与现有技术相比,本发明的有益效果是：采取将膨胀应力释放卸除的方法处理膨胀性岩土体,可以减小或消除膨胀应力,无需投入大量人力物力即可实现对于膨胀性岩土体的治理效果。(The invention relates to a method for treating expansive tunnel surrounding rocks, in particular to a method for relieving pressure of the expansive tunnel surrounding rocks, which comprises the following steps: (1) the disturbance range of the expansive surrounding rock caused by tunnel construction is ascertained; (2) the porosity n, the expansion rate alpha and the compressive strength sigma of the expansive surrounding rock test block are determined through tests ci (ii) a (3) Preliminarily determining the pressure relief and replacement position and depth of the expansive surrounding rock; (4) calculating the elastic modulus E of expansive surrounding rock m And compressive strength sigma cm (ii) a (5) Selecting the type of elastomer filling material; (6) calculating and determining the aperture, the depth, the number and the pitch of the pressure relief filling holes; compared with the prior art, the invention has the beneficial effects that: the expansive rock-soil body is processed by the method of releasing and removing the expansive stress, so that the expansive stress can be reduced or eliminated, and the treatment effect on the expansive rock-soil body can be realized without investing a large amount of manpower and material resources.)
1. A pressure relief method for expansive tunnel surrounding rock is characterized in that: the method comprises the following steps:
(1) the disturbance range of the expansive surrounding rock caused by tunnel construction is ascertained;
(2) the porosity n, the expansion rate alpha and the compressive strength sigma of the expansive surrounding rock test block are determined through testsci；
(3) Judging whether the tunnel needs pressure relief and replacement filling construction, and entering the step (4) if pressure relief and replacement filling are needed;
(4) preliminarily determining the pressure relief and replacement position and depth of the expansive surrounding rock;
(5) calculating the elastic modulus E of expansive surrounding rockmAnd compressive strength sigmacm；
(6) Selecting the type of the elastomer filling material according to the physical and mechanical parameters of the expansive surrounding rock;
(7) calculating and determining the aperture, the depth, the number and the pitch of the pressure relief filling holes;
(8) selecting an elastomer packing material with proper diameter and length;
(9) measuring the paying-off, positioning, pressure relief, hole position replacement and filling on the construction site, and drilling and hole blowing construction;
(10) filling the elastomer filling material into the pressure relief filling hole, and reserving a hole sealing section at the tail part;
(11) and (5) sealing the hole sealing section of the cement mortar filling pressure relief filling hole.
2. The method for relieving pressure of expansive tunnel surrounding rock according to claim 1, wherein the step (3) comprises the following specific steps:
1) obtaining a porosity mean value n and an expansion mean value a of the expansive rock (soil) test block according to the step (2) of claim 1;
2) judging whether pressure relief replacement construction is needed: if n is larger than or equal to alpha, pressure relief and replacement construction is not needed, and if n is smaller than alpha, pressure relief and replacement construction is needed.
3. The method for relieving pressure of expansive tunnel surrounding rock according to claim 1, wherein the step (4) comprises the following specific steps:
1) the step (1) of claim 1, obtaining the disturbance range of the expansive surrounding rock in the tunnel construction process;
2) and under the principle of not damaging better surrounding rocks, the pressure relief and replacement filling range is initially taken as the loosening range of the expansive surrounding rocks, and finally the pressure relief and replacement hole construction position and depth are comprehensively determined according to the calculation result, the geological condition, the construction condition and the control principle.
4. The method for relieving pressure of expansive tunnel surrounding rock of claim 1, wherein: modulus of elasticity E of the rock massmThe calculation process is as follows:
1) the compressive strength sigma of the rock test block is obtained by the testci；
2) Obtaining a geological strength index GSI through a GSI surrounding rock grading system of a Hoek-Brown strength criterion, and determining a rock mass disturbance coefficient D by combining the disturbance condition of construction on a tunnel rock mass;
3) the modulus of elasticity E of the rock mass is calculated by the following formulam：
When sigma isciWhen the pressure is less than or equal to 100MPa,
when sigma isciWhen the pressure is higher than 100MPa,
5. the method for relieving pressure of expansive tunnel surrounding rock of claim 1, wherein: compressive strength sigma of the rock masscmThe calculation formula of (2) is as follows:
wherein: s, mba-Hoek-Brown intensity criterion constant of rock-soil mass, calculated as follows:
wherein m isiIs the Hoek-Brown constant of the rock mass;
6. the method for relieving pressure of expansive tunnel surrounding rock of claim 1, wherein: the elastic modulus E of the soil body or rock-soil mixturemAnd compressive strength sigmacmThe determination process is as follows:
1) when the geology of the surrounding rock is the soil body, the elastic modulus E of the soil bodymThe compressive strength sigma of the soil body is calculated by an indoor triaxial compression testcmCan also be calculated by strength test;
2) when the surrounding rock geology has the rock mass and the soil mass, respectively calculating the elastic modulus and the compressive strength of the rock mass and the soil mass, and comprehensively obtaining the elastic modulus E of the rock-soil mixture of the geological areamAnd compressive strength sigmacm。
7. The method for relieving pressure in an expansive tunnel surrounding rock of claim 1, wherein the elastomer packing material selected in the step (6) satisfies the following requirements:
1) modulus of elasticity E of selected elastomer packing material1And the stress is less than the elastic modulus E of the rock (soil) bodymAnd compressive strength sigmacm；
2) The volume compressibility epsilon of the selected elastomer filling material is not less than 30%;
the elastomer filling material can be a solid elastic material or a grouting elastic material.
8. The method for relieving pressure of expansive tunnel surrounding rock according to claim 1, wherein the step (7) comprises the following specific steps:
1) calculating the expansion volume V of rock (soil) body after the rock (soil) body is expanded and filled with the pores of the rock and soil bodyβ；
2) The pressure relief replacement hole location and depth are initially determined according to the method of claim 4;
3) expansion volume V after filling the rock (soil) body pore space by expansion of expandable rock (soil) bodyβEqual to the compressed volume V of elastomer packing materialγAnd calculating the aperture, the depth, the number and the pitch of the pressure relief and filling holes under the deformation coordination condition.
9. The method for relieving pressure of expansive tunnel surrounding rock of claim 8, wherein: in the step 1), the expansion volume V of the expansive rock (soil) body after the expansive rock (soil) body is expanded to fill the pores of the rock (soil) bodyβThe calculation formula of (2) is as follows: vβ＝Vα-VVα · V-n · V, the porosity being
10. The method for relieving pressure of expansive tunnel surrounding rock of claim 8, wherein: the compression volume of the elastomer material is VγExpanded volume V after filling the pores of the expansive rock (earth) body by expansion of the expansive rock (earth) bodyβEqual to the compressed volume V of the elastomerγDeformation coordination condition Vβ＝VγAnd (3) calculating and determining parameters of the pressure relief hole, wherein the calculation formula is as follows:
in the formula, D is the pressure relief and filling hole diameter/the diameter of the elastomer material;
l is the length of the elastomer material, namely the pressure relief and filling hole replacing depth H minus the tail end reserved hole sealing section;
eta is the number of pressure relief and filling holes;
ε -the compressibility by volume of the elastomeric material.
11. The method for relieving pressure of expansive tunnel surrounding rock of claim 1, wherein:
1) in the calculation process of the pressure relief hole replacement and filling parameters, the disturbance range of the tunnel surrounding rock is preliminarily taken according to the pressure relief hole replacement and filling position and the depth under the principle of not damaging the better surrounding rock, and the deformation coordination condition V is adoptedβ＝VγDetermining the pressure relief pore-changing aperture D and the number eta of pressure relief holes;
2) when the pressure relief and pore-filling depth is taken as the disturbance depth of the tunnel surrounding rock to destroy the better surrounding rock or the calculated pressure relief and pore-filling pore diameter D and the number eta of the pressure relief pores are not reasonable, according to the deformation coordination condition Vβ＝VγRecalculating and determining the length L of the elastomer material, the depth H (H is L +0.2m) of the pressure relief replacement hole, the aperture D of the pressure relief hole and the number eta of the pressure relief holes;
3) and (3) judging whether the pressure relief and pore filling parameters of the step 1) and the step 2) of the claims are feasible or not according to geological conditions and actual construction conditions on site, and recalculating and determining the pressure relief and pore filling parameters according to the step 1) and the step 2) of the claims.
Technical Field
The invention relates to a treatment method for expansive tunnel surrounding rocks, in particular to a pressure relief method for the expansive tunnel surrounding rocks.
Background
The method has the advantages that the breadth of our country is broad, the engineering geological conditions are complex and changeable, the understanding of the expansive rock (soil) body is immature at present, a system theory and a technical system are not formed, and the dependence on engineering experience is more in the design and construction process. The method for treating the expansive rock (soil) body in the engineering is more traditional, and the traditional engineering measures of strengthening the structural strength, preventing water drainage and the like are adopted mainly by depending on the past engineering experience, namely an engineering analogy method. Even so, the treatment effect is still not ideal enough, and the existence of the expansive rock (soil) body still causes the structure to crack or even destroy. The reaction process leading to expansion is often irreversible and the expansion pressure, once generated, tends to increase substantially without diminishing with time. The expansion pressure brings huge potential safety hazards to tunnel construction and operation. If the expansion pressure can be released, thereby reducing or eliminating the expansion pressure acting on the tunnel lining structure, the adverse effect of the expandable rock (soil) body on the engineering can be greatly improved.
In the prior art, the method for treating the tunnel expansive rock (soil) body mainly adopts traditional engineering measures such as reinforcing the structural strength of a lining and preventing and draining water, and although a large amount of manpower and material resources are invested, the treatment effect on the expansive rock (soil) body is still not ideal in multiple engineering practices, and the expansive rock (soil) body still has great threat on engineering safety.
The method for drilling holes in the expansive rock (soil) body of the tunnel surrounding rock to perform pressure relief and replacement has no relevant application in relevant industries and engineering. Therefore, it is necessary to develop a comprehensive and effective pressure relief method to improve the treatment effect of the expansive rock (earth) body and to improve the long-term safety and stability of the engineering.
Therefore, the development of the pressure relief method for the expansive tunnel surrounding rock has urgent research value, and also has good economic benefit and industrial application potential, which is the basis and the place where the invention can be completed.
Disclosure of Invention
The present inventors have conducted intensive studies to overcome the above-identified drawbacks of the prior art, and as a result, have completed the present invention after having made a great deal of creative efforts.
Specifically, the technical problems to be solved by the present invention are: the method can absorb and bear the expansion deformation and expansion stress of the rock (soil) body, can realize a lasting pressure relief effect, and ensures the stability of the tunnel surrounding rock and the safety of a lining structure.
In order to achieve the purpose, the invention provides the following technical scheme:
a pressure relief method for expansive tunnel surrounding rock is characterized in that: the method comprises the following steps:
(1) the disturbance range of the expansive surrounding rock caused by tunnel construction is ascertained;
(2) the porosity n, the expansion rate alpha and the compressive strength sigma of the expansive surrounding rock test block are determined through testsci；
(3) Judging whether the tunnel needs pressure relief and replacement filling construction, and entering the step (4) if pressure relief and replacement filling are needed;
(4) preliminarily determining the pressure relief and replacement position and depth of the expansive surrounding rock;
(5) calculating the elastic modulus E of expansive surrounding rockmAnd compressive strength sigmacm；
(6) Selecting the type of the elastomer filling material according to the physical and mechanical parameters of the expansive surrounding rock;
(7) calculating and determining the aperture, the depth, the number and the pitch of the pressure relief filling holes;
(8) selecting an elastomer packing material with proper diameter and length;
(9) measuring the paying-off, positioning, pressure relief, hole position replacement and filling on the construction site, and drilling and hole blowing construction;
(10) filling the elastomer filling material into the pressure relief filling hole, and reserving a hole sealing section at the tail part;
(11) and (5) sealing the hole sealing section of the cement mortar filling pressure relief filling hole.
In the invention, as an improvement, the step (3) comprises the following specific steps:
1) obtaining a porosity mean value n and an expansion mean value a of the expansive rock (soil) test block according to the step (2) of
2) judging whether pressure relief replacement construction is needed: if n is larger than or equal to alpha, pressure relief and replacement construction is not needed, and if n is smaller than alpha, pressure relief and replacement construction is needed.
In the invention, as an improvement, the step (4) comprises the following specific steps:
1) the step (1) of
2) and under the principle of not damaging better surrounding rocks, the pressure relief and replacement filling range is initially taken as the loosening range of the expansive surrounding rocks, and finally the pressure relief and replacement hole construction position and depth are comprehensively determined according to the calculation result, the geological condition, the construction condition and the control principle.
In the present invention, as an improvement, the modulus of elasticity E of the rock massmThe calculation process is as follows:
1) the compressive strength sigma of the rock test block is obtained by the testci；
2) Obtaining a geological strength index GSI through a GSI surrounding rock grading system of a Hoek-Brown strength criterion, and determining a rock mass disturbance coefficient D by combining the disturbance condition of construction on a tunnel rock mass;
3) the modulus of elasticity E of the rock mass is calculated by the following formulam：
When sigma isciWhen the pressure is less than or equal to 100MPa,
when sigma isciWhen the pressure is higher than 100MPa,
in the present invention, as an improvement, the compressive strength σ of the rock masscmThe calculation formula of (2) is as follows:
wherein: s, mba-Hoek-Brown intensity criterion constant of rock-soil mass, calculated as follows:
wherein m isiIs the Hoek-Brown constant of the rock mass;
in the invention, as an improvement, the elastic modulus E of the soil body or the rock-soil mixturemAnd compressive strength sigmacmThe determination process is as follows:
1) when the geology of the surrounding rock is the soil body, the elastic modulus E of the soil bodymThe compressive strength sigma of the soil body is calculated by an indoor triaxial compression testcmCan also be calculated by strength test;
2) when the surrounding rock geology has the rock mass and the soil mass, respectively calculating the elastic modulus and the compressive strength of the rock mass and the soil mass, and comprehensively obtaining the elastic modulus E of the rock-soil mixture of the geological areamAnd compressive strength sigmacm。
In the present invention, as an improvement, the elastomer packing material selected in the step (6) should satisfy the following requirements:
1) modulus of elasticity E of selected elastomer packing material1And the stress is less than the elastic modulus E of the rock (soil) bodymAnd compressive strength sigmacm；
2) The volume compressibility epsilon of the selected elastomer filling material is not less than 30%;
the elastomer filling material can be a solid elastic material or a grouting elastic material.
In the invention, as an improvement, the step (7) comprises the following specific steps:
1) calculating the expansion volume V of rock (soil) body after the rock (soil) body is expanded and filled with the pores of the rock and soil bodyβ；
2) The pressure relief replacement hole location and depth are initially determined according to the method of
3) expansion body after expanding and filling rock (soil) body pore space by expansion rock (soil) bodyProduct VβEqual to the compressed volume V of elastomer packing materialγAnd calculating the aperture, the depth, the number and the pitch of the pressure relief and filling holes under the deformation coordination condition.
In the present invention, as an improvement, in step 1) of step (7), the expansive rock (earth) body expands to fill the expansion volume V after the pores of the rock (earth) body are filled with the expansive rock (earth) bodyβThe calculation formula of (2) is as follows: vβ＝Vα-VVα · V-n · V, the porosity being
In the present invention, as an improvement, the elastomeric material has a compressed volume VγExpanded volume V after filling the pores of the expansive rock (earth) body by expansion of the expansive rock (earth) bodyβEqual to the compressed volume V of the elastomerγDeformation coordination condition Vβ＝VγAnd (3) calculating and determining parameters of the pressure relief hole, wherein the calculation formula is as follows:
in the formula, D is the pressure relief and filling hole diameter/the diameter of the elastomer material;
l is the length of the elastomer material, namely the pressure relief and filling hole replacing depth H minus the tail end reserved hole sealing section;
eta is the number of pressure relief and filling holes;
ε -the compressibility by volume of the elastomeric material.
In the invention, as an improvement, the calculation process of the pressure relief and pore filling parameters is as follows:
1) in the calculation process of the pressure relief and pore-filling parameters, the principle of not damaging better surrounding rocks is adoptedAnd then, primarily taking the disturbance range of the tunnel surrounding rock according to the pressure relief and hole replacement position and depth, and according to the deformation coordination condition Vβ＝VγDetermining the pressure relief pore-changing aperture D and the number eta of pressure relief holes;
2) when the pressure relief and pore-filling depth is taken as the disturbance depth of the tunnel surrounding rock to destroy the better surrounding rock or the calculated pressure relief and pore-filling pore diameter D and the number eta of the pressure relief pores are not reasonable, according to the deformation coordination condition Vβ＝VγRecalculating and determining the length L of the elastomer material, the depth H (H is L +0.2m) of the pressure relief replacement hole, the aperture D of the pressure relief hole and the number eta of the pressure relief holes;
3) and (3) judging whether the pressure relief and pore filling parameters of the step 1) and the step 2) are feasible or not according to geological conditions and actual construction conditions on site, and if the parameters are not feasible, recalculating according to the step 1) and the step 2) to determine the pressure relief and pore filling parameters.
Compared with the prior art, the invention has the beneficial effects that:
(1) compared with the traditional treatment method of expansive rock (soil) bodies such as tunnel lining structure strength enhancement, waterproof and drainage improvement and the like, the method of releasing expansion stress is adopted to treat the expansive rock (soil) bodies of tunnel surrounding rocks, so that the influence of surrounding rock expansion pressure on the supporting structure can be greatly reduced or even eliminated, and the treatment effect on the expansive rock (soil) bodies can be realized without a large amount of manpower and material resources.
(2) After the drilling construction in the rock (soil) body, because the cross section size of the drilling position changes suddenly, the drilling position is easy to collapse and block due to the influence of stress concentration, if the drilling hole is filled with an elastomer material, the expansion deformation and the expansion stress of the rock (soil) body can be effectively born and absorbed, and the expansion deformation and the expansion stress of the rock (soil) body can also be deformed in cooperation with the expandable rock (soil) body, so that the condition that the cross section of the rock (soil) body changes suddenly is avoided, and the engineering problems that the stress concentration and the collapse occur frequently in the drilling of the rock (soil) body at present are solved.
(3) Compared with the traditional pressure relief holes, the elastic material is filled in the holes to complete hole sealing, so that the situation that the pressure relief holes become new underground water migration channels to accelerate the damage of surrounding rocks is effectively avoided, and the applicability of the pressure relief and replacement method for treating expansive surrounding rocks is improved.
Drawings
In order to more clearly illustrate the detailed description of the invention or the technical solutions in the prior art, the drawings that are needed in the detailed description of the invention or the prior art will be briefly described below. Throughout the drawings, like elements or portions are generally identified by like reference numerals. In the drawings, elements or portions are not necessarily drawn to scale.
FIG. 1 is a flow chart illustrating the steps of a pressure relief and refill method according to the present invention;
FIG. 2 is a circumferentially disposed cross-sectional view of a pressure relief refill bore hole of the present invention;
FIG. 3 is a longitudinally disposed cross-sectional view of a pressure relief refill bore hole of the present invention;
FIG. 4 is a schematic view of the pressure relief backfill material burying of the present invention;
in the figure: 1-pressure relief and radial boundary replacement; 2, pressure relief and hole replacement; 3, tunnel contour line; 4, tunnel surrounding rock; 5, pressure relief and filling annular boundary; 6-tunnel midline; 7-elastomer packing material; 8-cement mortar hole sealing section.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and therefore are only examples, and the protection scope of the present invention is not limited thereby.
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