CN117514357A - Surrounding rock instability early warning method for tunnel deformation monitoring - Google Patents
Surrounding rock instability early warning method for tunnel deformation monitoring Download PDFInfo
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- CN117514357A CN117514357A CN202311691548.0A CN202311691548A CN117514357A CN 117514357 A CN117514357 A CN 117514357A CN 202311691548 A CN202311691548 A CN 202311691548A CN 117514357 A CN117514357 A CN 117514357A
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- 239000011435 rock Substances 0.000 title claims abstract description 99
- 238000012544 monitoring process Methods 0.000 title claims abstract description 51
- 238000000034 method Methods 0.000 title claims abstract description 35
- 238000006243 chemical reaction Methods 0.000 claims abstract description 19
- 238000006073 displacement reaction Methods 0.000 claims abstract description 16
- 238000009412 basement excavation Methods 0.000 claims abstract description 10
- 238000009434 installation Methods 0.000 claims abstract description 5
- NAWXUBYGYWOOIX-SFHVURJKSA-N (2s)-2-[[4-[2-(2,4-diaminoquinazolin-6-yl)ethyl]benzoyl]amino]-4-methylidenepentanedioic acid Chemical compound C1=CC2=NC(N)=NC(N)=C2C=C1CCC1=CC=C(C(=O)N[C@@H](CC(=C)C(O)=O)C(O)=O)C=C1 NAWXUBYGYWOOIX-SFHVURJKSA-N 0.000 claims description 3
- 230000002706 hydrostatic effect Effects 0.000 claims description 3
- 238000010276 construction Methods 0.000 abstract description 6
- 230000000694 effects Effects 0.000 abstract description 2
- 230000006399 behavior Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F17/00—Methods or devices for use in mines or tunnels, not covered elsewhere
- E21F17/18—Special adaptations of signalling or alarm devices
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F17/00—Methods or devices for use in mines or tunnels, not covered elsewhere
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Abstract
The invention relates to the technical field of tunnel construction, in particular to a surrounding rock instability early warning method for tunnel deformation monitoring, which comprises the steps of determining the size of a cavity, the quality of rock mass and monitoring time, namely the distance s between a monitoring section and a tunnel face; calculating an axial displacement curve of tunnel excavation; solving the deformation delta of the installation position of the monitoring equipment according to the monitoring time, the axial displacement curve and the ground reaction curve s A percentage α of the total deformation δ of the surrounding rock; determination of rock mass ultimate strain epsilon j And peak failure strain ε p . According to the method, the early warning value in the tunnel excavation monitoring process is determined according to the longitudinal deformation rule of the tunnel in the tunnel excavation process and the limit strain and peak damage strain of the rock mass, the obtained deformation early warning value is combined with the monitoring data, the stable state of the underground rock tunnel can be effectively judged, and the safety performance and the effect of construction are improved.
Description
Technical Field
The invention relates to the technical field of tunnel construction, in particular to a surrounding rock instability early warning method for tunnel deformation monitoring.
Background
With the continuous development of underground engineering such as water conservancy and hydropower, more and more underground tunnel engineering is implemented.
In underground tunnel engineering, analysis of deformation monitoring data is an important means for guaranteeing safe construction of underground engineering, in tunnel excavation, deformation monitoring early warning values are related to factors such as surrounding rock mass quality, monitoring time and chamber size of a tunnel, but no accurate theories exist so far how to evaluate the current stability of the tunnel according to the magnitude of the deformation monitoring data.
Disclosure of Invention
The invention aims to provide a surrounding rock instability early warning method for tunnel deformation monitoring, which aims to solve the problem of how to evaluate the current stability of a tunnel according to the magnitude of deformation monitoring data in the background technology.
In order to achieve the above purpose, the invention provides the following technical scheme, namely a surrounding rock instability early warning method for tunnel deformation monitoring:
1) Determining the size of a cavity, the mass of a rock mass and monitoring time, namely the distance s between a monitoring section and a face;
2) Calculating an axial displacement curve of tunnel excavation, wherein the axial displacement curve can be solved by the following formula:
wherein: delta is the maximum deformation of surrounding rock behind the tunnel face; delta s Is the deformation amount of a certain position behind the face; s is the deformation delta s Distance from the face; r is the tunnel radius.
The maximum deformation delta of surrounding rock behind the tunnel face can be determined through a ground reaction curve, and the concrete method is as follows:
after the cavity is excavated, the stress of the rock mass around the cavity and the far field stress can be calculated according to the following formula:
wherein a and b are rock mass quality parameters; sigma (sigma) ci The uniaxial compressive strength of the rock mass is expressed in MPa; ρ is the supporting force in MPa.
The ground reaction curve can be divided into an elastic section and a plastic section, and the two parts are separately solved when the ground reaction curve is solved, and the stress limit when the elastic and plastic are turned is defined as sigma fy The stress limit is defined as sigma fy Can be calculated by the following formula:
when sigma is i ≥σ fy At the moment, the surrounding rock is in an elastic stage, and the deformation X 1 The method comprises the following steps:
g in jq Is the shear modulus of the rock mass, MPa; r is the tunnel radius, m.
When sigma is i ＜σ fy When the development depth D of the surrounding rock plastic region is:
at this time, the surrounding rock deforms X 2 Can be expressed as:
wherein p is the Poisson's ratio of rock mass, K θ ＝[1+sinθ]/[1-sinθ]θ is the rock mass shear angle.
According to the formula, a theoretical ground reaction curve of tunnel excavation can be calculated, and delta is calculated.
3) Solving the deformation delta of the installation position of the monitoring equipment according to the monitoring time, the axial displacement curve and the ground reaction curve s A percentage α of the total deformation δ of the surrounding rock;
4) Determination of rock mass ultimate strain epsilon j And peak failure strain ε p ；
5) According to the residual deformation X of the tunnel after the monitoring equipment is installed C Limit strain epsilon j Peak failure strain epsilon p Solving the early warning value Y 1 ＝Rε j (1-alpha) early warning value Y 2 ＝Rε p (1- α), wherein α=δ s And/delta, R is the radius of the tunnel. The specific standard is as follows:
I. when deformation x < Y 1 When the cavity is in a stable state;
when deformed Y 1 ≤x＜Y 2 When the tunnel is stable, a certain risk exists, attention needs to be paid, and the support structure is checked;
III when deformation x is greater than or equal to Y 2 When the cavern is stable, the risk exists, and the support needs to be enhancedAnd increasing the observation frequency;
and x is the actual monitoring deformation.
Preferably, the theoretical formula of the axial displacement curve and the ground reaction curve is suitable for the initial ground stress field characteristics of a circular section and hydrostatic pressure, and the numerical model is suitable for various conditions, and if the conditions are more complicated, the numerical model can be used for solving.
Preferably, the limit strain ε j : when the strain of the cavity is smaller than or equal to the strain, the cavity can be stabilized without special support, namely, when the strain of the cavity is smaller than or equal to the strain, the cavity is in a stable state, and if the strain of the cavity is larger than the strain, the cavity is stabilized with a certain risk.
Preferably, the limit strain ε j The solving method is as follows:
from formula (8):
wherein: sigma (sigma) ck The uniaxial compressive strength of the rock mass; sigma (sigma) ct The uniaxial compressive strength of the rock mass; e (E) k Is the elastic modulus of the rock mass; e (E) t Is the elastic modulus of the rock mass; g is the score of the mass of the rock mass.
The rock uniaxial compressive strength sigma of the basic parameter rock mass can be obtained by the rock mass quality according to the formula (9) ck Elastic modulus E of rock mass k Solving the limit strain epsilon by the score G of the rock mass j 。
Preferably, the peak failure strain ε p : when the strain of the cavity is larger than the strain, the cavity has a certain safety risk without special support.
Preferably, the peak damage strain solving method is as follows:
the limit strain of about 1.5 times the peak strain at break is known from the formula (10).
Compared with the prior art, the invention has the beneficial effects that:
this method is based on the insight that the tunnel deforms regularly along the axis, taking into account the behaviour of the rock mass under extreme strain and peak failure strain. By systematic analysis of these factors, we can make scientific and reasonable deformation early warning values, so that potential problems can be found in advance, and appropriate measures can be taken to ensure the stability of underground caverns.
By comprehensively considering the data of deformation monitoring and rock mass behaviors, the method not only enables stability evaluation of underground rock caverns to be more accurate, but also provides powerful support for construction. Through real-time monitoring and timely early warning, a constructor can take rapid and effective countermeasures, so that potential risks are reduced to the greatest extent, and safe running of tunnel engineering is ensured. The application of the method is beneficial to improving the construction safety and engineering effect under complex geological conditions, and provides a scientific and feasible monitoring and early warning means for the sustainable development of underground engineering.
Drawings
FIG. 1 is a schematic diagram of the invention for monitoring the position relationship between a section and a face and monitoring the deformation of the section and the maximum deformation of surrounding rock;
FIG. 2 is a schematic illustration of the axial displacement curve and ground response curve of the present invention;
FIG. 3 is a schematic view of an exemplary monitoring section and monitoring point arrangement of the present invention
Detailed Description
Referring to fig. 1-3, an embodiment of the present invention is provided:
a tunnel deformation early warning value determining method comprises the following steps:
1) Determining the size of a cavity, the mass of a rock mass and monitoring time, namely the distance s between a monitoring section and a face;
2) Calculating an axial displacement curve of tunnel excavation, wherein the axial displacement curve can be solved by the following formula:
wherein: delta is the maximum deformation of surrounding rock behind the tunnel face; delta s Is the deformation amount of a certain position behind the face; s is the deformation delta s Distance from the face; r is the tunnel radius.
The maximum deformation delta of surrounding rock behind the tunnel face can be determined through a ground reaction curve, and the concrete method is as follows:
after the cavity is excavated, the stress of the rock mass around the cavity and the far field stress can be calculated according to the following formula:
wherein a and b are rock mass quality parameters; sigma (sigma) ci The uniaxial compressive strength of the rock mass is expressed in MPa; ρ is the supporting force in MPa.
The ground reaction curve can be divided into an elastic part and a plastic part, the two parts are separately solved when the ground reaction curve is solved, and the stress limit when the elastic part and the plastic part are turned is defined as sigma fy The stress limit is defined as sigma fy Can be calculated by the following formula:
when sigma is i ≥σ fy At the moment, the surrounding rock is in an elastic stage, and the deformation X 1 The method comprises the following steps:
g in jq Is a shear die for rock massThe amount is MPa; r is the tunnel radius, m.
When sigma is i ＜σ fy When the development depth D of the surrounding rock plastic region is:
at this time, the surrounding rock deforms X 2 Can be expressed as:
wherein p is the Poisson's ratio of rock mass, K θ ＝[1+sinθ]/[1-sinθ]θ is the rock mass shear angle.
According to the formula, a theoretical GRC curve of tunnel excavation can be calculated, and delta is calculated.
The theoretical formula of the axial displacement curve and the ground reaction curve is suitable for the initial ground stress field characteristics of a circular section and hydrostatic pressure, and the numerical model is suitable for various conditions, and if the conditions are more complex, the numerical model can be used for solving.
3) Solving the deformation delta of the installation position of the monitoring equipment according to the monitoring time, the axial displacement curve and the ground reaction curve s A percentage α of the total deformation δ of the surrounding rock;
4) Determination of rock mass ultimate strain epsilon j And peak failure strain ε p ；
Limit strain epsilon j : when the strain of the cavity is smaller than or equal to the strain, the cavity can be stabilized without special support, namely, when the strain of the cavity is smaller than or equal to the strain, the cavity is in a stable state, and if the strain of the cavity is larger than the strain, the cavity is stabilized with a certain risk.
Limit strain epsilon j The solving method is as follows:
from formula (8):
wherein: sigma (sigma) ck The uniaxial compressive strength of the rock mass; sigma (sigma) ct The uniaxial compressive strength of the rock mass; e (E) k Is the elastic modulus of the rock mass; e (E) t Is the elastic modulus of the rock mass; g is the score of the mass of the rock mass.
The rock uniaxial compressive strength sigma of the basic parameter rock mass can be obtained by the rock mass quality according to the formula (9) ck Elastic modulus E of rock mass k Solving the limit strain epsilon by the score G of the rock mass j 。
Peak failure strain epsilon p : when the strain of the cavity is larger than the strain, the cavity has a certain safety risk without special support.
The peak damage strain solving method is as follows:
the limit strain of about 1.5 times the peak strain at break is known from the formula (10).
5) According to the residual deformation X of the tunnel after the monitoring equipment is installed C Limit strain epsilon j Peak failure strain epsilon p Solving the early warning value Y 1 ＝Rε j (1-alpha) early warning value Y 2 ＝Rε p (1- α), wherein α=δ s And/delta, R is the radius of the tunnel. The specific standard is as follows:
I. when deformation x < Y 1 When the cavity is in a stable state;
when deformed Y 1 ≤x＜Y 2 When the tunnel is stable, a certain risk exists, attention needs to be paid, and the support structure is checked;
III when deformation x is greater than or equal to Y 2 When the cavern is stable, the risk exists, the support needs to be enhanced, and the observation frequency is increased;
and x is the actual monitoring deformation.
Working principle:
the implementation step one: determining the size of a cavity, R; determining surrounding rock parameters: uniaxial compressive strength sigma of rock mass ck Elastic modulus E of rock mass k A score G of rock mass;
and implementation step two: and installing monitoring equipment, and determining the distance s between the equipment and the face during installation.
And carrying out the step III: solving an axial displacement curve and a ground reaction curve, and determining deformation delta of the position of the monitoring equipment s The percentage alpha and the limit strain epsilon of the total deformation delta of the surrounding rock j Peak failure strain epsilon p 。
And carrying out the step four: according to the percentage alpha, the limit strain epsilon j Peak failure strain epsilon p Find the early warning value Y 1 ＝Rε j (1-alpha) early warning value Y 2 ＝Rε p (1-α)；
And carrying out the step five: and evaluating the current stable state of the tunnel according to the monitoring data.
Claims (6)
1. The utility model provides a surrounding rock instability early warning method for tunnel deformation monitoring, which is characterized by comprising the following steps:
1) Determining the size of a cavity, the mass of a rock mass and monitoring time, namely the distance s between a monitoring section and a face;
2) Calculating an axial displacement curve of tunnel excavation, wherein the axial displacement curve can be solved by the following formula:
wherein: delta is the maximum deformation of surrounding rock behind the tunnel face; delta s Is the deformation amount of a certain position behind the face; s is the deformation delta s Distance from the face; r is the tunnel radius.
The maximum deformation delta of surrounding rock behind the tunnel face can be determined through a ground reaction curve, and the concrete method is as follows:
after the cavity is excavated, the stress of the rock mass around the cavity and the far field stress can be calculated according to the following formula:
wherein a and b are rock mass quality parameters; sigma (sigma) ci The uniaxial compressive strength of the rock mass is expressed in MPa; ρ is the supporting force in MPa.
The ground reaction curve can be divided into an elastic section and a plastic section, and the two parts are separately solved when the ground reaction curve is solved, and the stress limit of the elastoplastic turning point is defined as sigma fy The stress limit is defined as sigma fy Can be calculated by the following formula:
when sigma is i ≥σ fy At the moment, the surrounding rock is in an elastic stage, and the deformation X 1 The method comprises the following steps:
g in jq Is the shear modulus of the rock mass, MPa; r is the tunnel radius, m.
When sigma is i <σ fy When the development depth D of the surrounding rock plastic region is:
at this time, the surrounding rock deforms X 2 Can be expressed as:
wherein p is the Poisson's ratio of rock mass, K θ ＝[1+sinθ]/[1-sinθ]θ is the rock mass shear angle.
According to the formula, a theoretical ground reaction curve of tunnel excavation can be calculated, and delta is calculated.
3) Solving the deformation delta of the installation position of the monitoring equipment according to the monitoring time and the axis displacement curve and the ground reaction curve s A percentage α of the total deformation δ of the surrounding rock;
4) Determination of rock mass ultimate strain epsilon j And peak failure strain ε p ；
5) According to the residual deformation X of the tunnel after the monitoring equipment is installed C Limit strain epsilon j Peak failure strain epsilon p Solving the early warning value Y 1 ＝Rε j (1-alpha) early warning value Y 2 ＝Rε p (1- α), wherein α=δ s And/delta, R is the radius of the tunnel. The specific standard is as follows:
I. when deformed x<Y 1 When the cavity is in a stable state;
when deformed Y 1 ≤x<Y 2 When the tunnel is stable, a certain risk exists, attention needs to be paid, and the support structure is checked;
III when deformation x is greater than or equal to Y 2 When the cavern is stable, the risk exists, the support needs to be enhanced, and the observation frequency is increased;
and x is the actual monitoring deformation.
2. The method for pre-warning surrounding rock instability for tunnel deformation monitoring according to claim 1, wherein the method is characterized in that: the theoretical formula of the axial displacement curve and the ground reaction curve is suitable for the hydrostatic pressure characteristics of the annular section and the initial ground stress field, the numerical model is suitable for various conditions, and if the conditions are more complex, the numerical model can be used for solving.
3. The method for pre-warning surrounding rock instability for tunnel deformation monitoring according to claim 1, wherein the method is characterized in that: the ultimate strain ε j : when the strain of the finger cavity is less than or equal to that of the cavityThe chamber can be stabilized without special support, namely, the chamber is in a stable state when the chamber strain is smaller than or equal to the value, and if the chamber strain is larger than the value, the chamber is stabilized with a certain risk.
4. The method for pre-warning surrounding rock instability for tunnel deformation monitoring according to claim 3, wherein the method is characterized in that: the ultimate strain ε j The solving method is as follows:
from formula (8):
wherein: sigma (sigma) ck The uniaxial compressive strength of the rock mass; sigma (sigma) ct The uniaxial compressive strength of the rock mass; e (E) k Is the elastic modulus of the rock mass; e (E) t Is the elastic modulus of the rock mass; g is the score of the mass of the rock mass.
The rock uniaxial compressive strength sigma of the basic parameter rock mass can be obtained by the rock mass quality according to the formula (9) ck Elastic modulus E of rock mass k Solving the limit strain epsilon by the score G of the rock mass j 。
5. The method for pre-warning surrounding rock instability for tunnel deformation monitoring according to claim 1, wherein the method is characterized in that: the peak failure strain ε p : when the strain of the cavity is larger than the strain, the cavity has a certain safety risk without special support.
6. The method for pre-warning surrounding rock instability for tunnel deformation monitoring according to claim 5, wherein the method is characterized in that: the peak damage strain solving method is as follows:
the limit strain of about 1.5 times the peak strain at break is known from the formula (10).
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