Phyllite tunnel surrounding rock large deformation risk discrimination method, device and product

Abstract

The embodiment of the present application provides a phyllite tunnel surrounding rock large deformation risk discrimination method, device and product, and relates to the field of rock mechanics. In the embodiment of the present application, based on Hoek-Brown criterion, the value of soft rock GSI is quantified by introducing rock mass blockiness index coefficient RBI and rock block damage index VI, the surrounding rock geological damage degree is obtained by using the residual strength method, compared with the maximum creep cracking damage obtained by indoor test, and the preliminary identification method of the large deformation of the surrounding rock in the field is established. Thus, the engineering geological characteristics can be obtained by surveying the unexcavated surrounding rock, and then the rock mass geological damage degree and the maximum creep cracking damage are calculated based on the engineering geological characteristics, so as to preliminarily identify whether the surrounding rock of the unexcavated section of the tunnel has the large deformation risk, thereby guiding the tunnel excavation and support of the subsequent to-be-excavated section, and providing a reliable basis for the disaster reduction and prevention of large deformation disasters in the field of tunnels and underground engineering.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the field of rock mechanics, in particular to a phyllite tunnel surrounding rock large deformation risk discrimination method, device and product. BACKGROUND

[0002] The western region of China is affected by the collision and extrusion of the Indian plate and the Eurasian plate, the uplift of the Qinghai-Tibet Plateau and the incision of rivers, and has large terrain undulations, complex stratum lithology and geological structure, strong fault activity, high ground stress and frequent geological disasters. Under this special geological background and complex engineering environment, deep and long tunnels built in soft rock or broken rock mass often face the threat of large deformation disasters during construction. According to incomplete statistics, there are more than 50 tunnels that have experienced large deformation disasters in the western region of China. The western plateau region of Sichuan is located in the eastern margin of the Qinghai-Tibet Plateau and the Hengduan Mountains, which is the transition zone between the first and second steps in China. The terrain has a large height difference, and the geological conditions are extremely complex. Many major transportation infrastructure projects (such as the Wenma Expressway, Jiuzhou Expressway, Chengdu-Lanzhou Railway and Sichuan-Tibet Railway) currently under construction face serious tunnel extrusion and large deformation disasters. Among them, the soft rock large deformation section of the Yangjiaping Tunnel accounts for more than 90% of the entire tunnel length (12815m); the Wenma Expressway, the Ganbao Tunnel and the Miaola No. 3 Tunnel all face serious extrusion and large deformation disasters, and the Sichuan-Tibet Railway has a tunnel ratio of 82%. There are many super-long and deep-buried tunnels, and the tunnel projects in Sichuan are affected by the active internal and external dynamic geological effects and weak rock, and will face the severe challenge of surrounding rock large deformation disasters. Therefore, extrusion and large deformation disasters have seriously restricted the development of the western region of China and have become a major technical problem that needs to be solved in the field of tunnel engineering and disaster prevention and mitigation.

[0003] However, existing research results and technical level are still insufficient to better solve the problem of tunnel large deformation in engineering construction, and there is a lack of mature technical standards and specifications for the prevention and control of tunnel large deformation in engineering practice. The prevention and control of large deformation disasters are still in the exploratory stage of experience. At present, in terms of high ground stress causes and evaluation, the combination of macro-geological environment evolution and micro-rock mass mechanical testing and simulation is weak, and there are technical bottlenecks in the quantitative evaluation of high ground stress of soft and broken surrounding rock tunnels. In terms of large deformation disaster mechanism, there is less discussion on the constitutive mechanics model of large deformation surrounding rock and the geological pattern of large deformation disaster, especially the mechanism and quantitative analysis of long-term stability of soft rock under hydraulic coupling conditions.

[0004] Therefore, there is an urgent need for a phyllite tunnel surrounding rock large deformation risk discrimination method to provide a basis for the prevention and control of tunnel large deformation. SUMMARY

[0005] Embodiments of the present application provide a phyllite tunnel surrounding rock large deformation risk discrimination method, device and product to at least partially solve the problems in the related art.

[0006] The first aspect of the embodiments of the present application provides a phyllite tunnel surrounding rock large deformation risk discrimination method, which comprises:

[0007] determining a current phyllite surrounding rock current permeation pressure and a current confining pressure;

[0008] obtaining a rock mass blockiness index RBI and a rock block damage index VI of the current phyllite surrounding rock according to engineering geological characteristics of the current phyllite surrounding rock, the engineering geological characteristics being obtained by drilling sampling on the current phyllite surrounding rock;

[0009] determining a GSI value according to the rock mass blockiness index RBI and the rock block damage index VI of the current phyllite surrounding rock, determining a strength of the current phyllite surrounding rock according to the GSI value and Hoek-Brown criterion, and determining a geological damage degree of the current phyllite surrounding rock according to the strength;

[0010] determining an upper limit value of cracking damage of the phyllite surrounding rock under the current permeation pressure and the current confining pressure according to saturated phyllite triaxial creep test results under seepage-stress conditions;

[0011] in the case that the geological damage degree is not less than the upper limit value of cracking damage, discriminating that the current phyllite surrounding rock has a large deformation risk.

[0012] Optionally, determining a GSI value according to the rock mass blockiness index RBI and the rock block damage index VI of the current phyllite surrounding rock, determining a strength of the current phyllite surrounding rock according to the GSI value and Hoek-Brown criterion, and determining a geological damage degree of the current phyllite surrounding rock according to the strength, comprises:

[0013] measuring a length of a drilled core of the current phyllite surrounding rock collected;

[0014] defining percentages of drilled cores with lengths of 3-10 cm, 10-30 cm, 30-50 cm, 50-100 cm and more than 100 cm as weights, multiplying the weights by corresponding coefficients and summing up to obtain the rock mass blockiness index RBI of the current phyllite surrounding rock;

[0015] determining a rock block damage index VI of the phyllite surrounding rock under the current permeation pressure and the current confining pressure according to saturated phyllite triaxial creep test results under seepage-stress conditions;

[0016] determining a GSI value according to the rock mass blockiness index RBI and the rock block damage index VI;

[0017] According to the Hoek-Brown criterion and the GSI value, the strength of the current phyllite surrounding rock is obtained;

[0018] According to the strength of the current phyllite surrounding rock, a short-term load peak strength of intact phyllite is determined, and the short-term load peak strength of intact phyllite is obtained according to a triaxial creep experiment of saturated phyllite under seepage-stress conditions.

[0019] Optionally, the determination of the rock mass damage index VI of the phyllite surrounding rock under the current seepage pressure and the current confining pressure according to the triaxial creep experiment results of saturated phyllite under seepage-stress conditions comprises:

[0020] A crack initiation damage calculation value table corresponding to different stress intensity ratios under different confining pressures is obtained by combining the stress intensity ratio and the triaxial creep experiment results of saturated phyllite under seepage-stress conditions.

[0021] The stress intensity ratio and the ratio of the confining pressure to the peak strength σ3 / σ0 are taken as independent variables, and the crack initiation damage is taken as a dependent variable, linear regression analysis is performed, and a corresponding relationship between the stress intensity ratio, the ratio of the confining pressure to the peak strength, and the crack initiation damage is obtained.

[0022] The current phyllite damage index VI0 is obtained according to the corresponding relationship and the current stress intensity ratio σ / σ0 and the current confining pressure intensity ratio σ3 / σ0.

[0023] The phyllite damage index VI0 is corrected by using a groundwater correction coefficient λ to obtain a rock mass damage index under seepage: VI = λVI0.

[0024] The groundwater correction coefficient λ is fitted based on the damage amount of the indoor seepage creep test and the triaxial creep damage amount: λ = 0.00656P 2 + 1.10818.

[0025] P represents the current seepage pressure of the current phyllite surrounding rock; σ3 represents the current confining pressure of the current phyllite surrounding rock; σ0 represents the saturated peak strength of the phyllite surrounding rock, and σ represents the stress of the current phyllite surrounding rock.

[0026] Optionally, according to the triaxial creep experiment results of saturated phyllite under seepage-stress conditions, the upper limit value of the crack initiation damage under the current seepage pressure and the current confining pressure is fitted and determined.

[0027] According to the triaxial creep experiment results of saturated phyllite under seepage-stress conditions, a corresponding relationship between the upper limit value of the crack initiation damage of phyllite and the confining pressure and the seepage pressure is fitted.

[0028] According to the correspondence, the cracking damage upper limit value of the current phyllite surrounding rock under the current osmotic pressure and the current confining pressure is determined.

[0029] Optionally, the method further comprises:

[0030] For unexcavated phyllite surrounding rock, an advanced drill hole and a monitoring point are arranged on the working face;

[0031] The advanced drill hole corresponds to the position of the monitoring point, the monitoring point is used to measure the current osmotic pressure and the current confining pressure of the current phyllite surrounding rock, and the advanced drill hole is used to obtain the engineering geological characteristics of the current phyllite surrounding rock.

[0032] The second aspect of the embodiment of the application provides a surrounding rock large deformation risk discrimination device for a phyllite tunnel, and the device comprises:

[0033] A first determination module is configured to determine the current osmotic pressure and the current confining pressure of the current phyllite surrounding rock.

[0034] A second determination module is configured to obtain the rock mass blockiness index RBI and the rock block damage index VI of the current phyllite surrounding rock according to the engineering geological characteristics of the current phyllite surrounding rock, wherein the engineering geological characteristics are obtained by drilling sampling on the current phyllite surrounding rock.

[0035] A third determination module is configured to determine the GSI value according to the rock mass blockiness index RBI and the rock block damage index VI of the current phyllite surrounding rock, determine the strength of the current phyllite surrounding rock according to the GSI value and the Hoek-Brown criterion, and determine the geological damage degree of the current phyllite surrounding rock according to the strength.

[0036] A fourth determination module is configured to determine the cracking damage upper limit value of the phyllite surrounding rock under the current osmotic pressure and the current confining pressure according to the triaxial creep test results of the saturated phyllite under the seepage-stress condition.

[0037] A discrimination module is configured to discriminate that the current phyllite surrounding rock has a large deformation risk in the case that the geological damage degree is not less than the cracking damage upper limit value.

[0038] Optionally, the third determination module comprises:

[0039] A measurement sub-module is configured to measure the length of the collected drill core of the current phyllite surrounding rock.

[0040] A first sub-module is configured to define the percentage of the drill core with the measured length of 3-10 cm, 10-30 cm, 30-50 cm, 50-100 cm and more than 100 cm as a weight, multiply the weight by a corresponding coefficient and sum up to obtain the rock mass blockiness index RBI of the current phyllite surrounding rock.

[0041] a second determining sub-module, configured to determine a rock mass damage index VI of the phyllite surrounding rock under a current seepage pressure and a current confining pressure according to a saturated phyllite triaxial creep experiment result under seepage-stress conditions;

[0042] a third determining sub-module, configured to determine a GSI value according to the rock mass blockiness index RBI and the rock mass damage index VI;

[0043] a fourth determining sub-module, configured to obtain a strength of the current phyllite surrounding rock according to the Hoek-Brown criterion and the GSI value;

[0044] a fifth determining sub-module, configured to determine a geological damage degree of the current phyllite surrounding rock according to the strength of the current phyllite surrounding rock and a short-term load peak strength of intact phyllite, the short-term load peak strength of intact phyllite being obtained according to a saturated phyllite triaxial creep experiment result under seepage-stress conditions.

[0045] Optionally, the second determining sub-module is specifically configured to:

[0046] obtain a crack damage calculation value table corresponding to different confining pressures and stress intensity ratios according to stress intensity ratios and the saturated phyllite triaxial creep experiment result under seepage-stress conditions;

[0047] perform linear regression analysis on the stress intensity ratios and the ratio of the confining pressure to the peak strength σ3 / σ0 as independent variables and the crack damage as a dependent variable, to obtain a corresponding relationship between the stress intensity ratios and the ratio of the confining pressure to the peak strength and the crack damage:

[0048] obtain a current phyllite damage index VI0 according to the corresponding relationship and a current stress intensity ratio σ / σ0 and a current confining pressure intensity ratio σ3 / σ0;

[0049] correct the phyllite damage index VI0 by using a groundwater correction coefficient λ to obtain a rock mass damage index under seepage: VI = λVI0;

[0050] wherein the groundwater correction coefficient λ is obtained by fitting a damage amount of an indoor seepage creep experiment and a triaxial creep damage amount: λ = 0.00656P + 1.10818; 2

[0051] wherein P represents a current seepage pressure of the current phyllite surrounding rock, σ3 represents a current confining pressure of the current phyllite surrounding rock, σ0 represents a saturated peak strength of the phyllite surrounding rock, and σ represents a stress of the current phyllite surrounding rock.

[0052] Optionally, the fourth determining module is specifically configured to:

[0053] ​According to the triaxial creep test results of the saturated phyllite under seepage-stress conditions, a corresponding relationship between the cracking damage upper limit value of the phyllite and the confining pressure and the seepage pressure is fitted;

[0054] According to the corresponding relationship, the cracking damage upper limit value under the current seepage pressure and the current confining pressure is determined.

[0055] Optionally, the device further comprises:

[0056] The arrangement module is configured to arrange, for the unexcavated phyllite surrounding rock, an advanced borehole and a monitoring point on the working face.

[0057] The advanced borehole corresponds to the monitoring point position, the monitoring point is used to measure the current seepage pressure and the current confining pressure of the current phyllite surrounding rock, and the advanced borehole is used to obtain the engineering geological characteristics of the current phyllite surrounding rock.

[0058] The third aspect of the embodiment of the present application provides a computer readable storage medium, which stores a computer program, and the program is executed by a processor to realize the steps in the method of the first aspect of the present application.

[0059] The fourth aspect of the embodiment of the present application provides an electronic device, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor realizes the steps in the method of the first aspect of the present application when executed.

[0060] In the embodiment of the present application, based on the Hoek-Brown criterion, the value of GSI (geological strength index) of soft rock is quantified by introducing rock-mass block index RBI (rock-mass block index) and rock block damage index VI (vulnerability index), and the residual strength method is used to obtain the rock mass geological damage degree, which is compared with the maximum creep cracking damage value obtained by the laboratory test to establish a preliminary identification method for large deformation of the surrounding rock on site. In the embodiment of the present application, the engineering geological characteristics can be obtained by surveying the unexcavated surrounding rock, and then the rock mass geological damage degree and the maximum creep cracking damage value are calculated based on the engineering geological characteristics, so as to preliminarily identify whether the surrounding rock of the unexcavated section of the tunnel has a large deformation risk, thereby guiding the tunnel excavation and support of the subsequent to-be-excavated section, and providing a reliable basis for disaster reduction and prevention of large deformation disasters in the field of tunnels and underground engineering. BRIEF DESCRIPTION OF DRAWINGS

[0061] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative labor.

[0062] Figure 1 is a flow chart of a large deformation risk discrimination method of a phyllite tunnel surrounding rock of an embodiment of the present application;

[0063] Figure 2 is a flow chart of another large deformation risk discrimination method of a phyllite tunnel surrounding rock of an embodiment of the present application;

[0064] Figure 3 is a schematic diagram of an overburden layer near a surrounding rock working face in an implementation case of an embodiment of the present application;

[0065] Figure 4 is a schematic diagram of a surrounding rock lithology of a working face in an implementation case of an embodiment of the present application;

[0066] Figure 5 is a schematic diagram of a position of an advanced geological drill hole arranged on a surrounding rock working face and a distribution of monitoring points after excavation in an implementation case of an embodiment of the present application;

[0067] Figure 6 is a schematic diagram of monitoring data of a surrounding rock deformation of each monitoring point after excavation of a surrounding rock in an implementation case of an embodiment of the present application;

[0068] Figure 7 is a structural block diagram of a large deformation risk discrimination device of a phyllite tunnel surrounding rock of an embodiment of the present application. DETAILED DESCRIPTION

[0069] In order to make the above-mentioned purposes, features and advantages of the present application more apparent and easy to understand, the following will further describe the present application in combination with the drawings and specific embodiments.

[0070] Referring to Figure 1 , a flow chart of a large deformation risk discrimination method of a phyllite tunnel surrounding rock of an embodiment of the present application is shown, and the large deformation risk discrimination method of the phyllite tunnel surrounding rock provided by the embodiment of the present application can include the following steps:

[0071] S101, determining a current phyllite surrounding rock current permeation pressure and a current confining pressure.

[0072] In the embodiment of the present application, when discriminating a large deformation risk for a specific tunnel, a plurality of typical monitoring points can be selected, and each monitoring point is analyzed and judged as a current phyllite surrounding rock.

[0073] In the embodiment of the present application, the current permeation pressure and the current confining pressure of the current phyllite surrounding rock can be determined by on-site investigation of the current phyllite surrounding rock.

[0074] In S102, the rock mass blockiness index RBI and the rock block damage index VI of the current phyllite surrounding rock are obtained according to the engineering geological characteristics of the current phyllite surrounding rock.

[0075] The engineering geological characteristics are obtained by drilling sampling of the current phyllite surrounding rock.

[0076] In the embodiment of the present application, the current phyllite surrounding rock can be sampled by the commonly used drilling sampling method in the art, and the engineering geological characteristics of the current phyllite surrounding rock are analyzed according to the collected core, so as to obtain the rock mass blockiness index RBI and the rock block damage index VI of the current phyllite surrounding rock.

[0077] In the embodiment of the present application, the rock mass blockiness index RBI can comprehensively represent the size of the rock mass blockiness, the structure type and the mutual combination relationship of the structure, and the larger the RBI value is, the more complete the rock mass is and the fewer the joint fissures are.

[0078] The damage law of phyllite in the creep process can be divided into nucleation damage in the constant speed creep stage and extension damage in the accelerated creep stage, and the surrounding rock large deformation is a process from stability to instability, and when the rock damage degree exceeds the maximum value of the cracking damage, the creep will change from stability to instability, so the damage accumulation evolution law in the constant speed creep stage is a key index for identifying large deformation. Practice shows that the surrounding rock will deform rapidly after excavation to form a plastic circle, which is also the theoretical basis of the New Austrian Tunneling Method, so in the embodiment of the present application, the initial state of the rock mass for preliminary identification corresponds to the constant speed creep stage.

[0079] In the embodiment of the present application, the rock block damage index VI can be determined by combining the stress intensity ratio with the triaxial creep test results of saturated phyllite under seepage-stress conditions.

[0080] In the embodiment of the present application, triaxial creep test is carried out on the saturated phyllite, the permeation pressure and the confining pressure are controlled to be the current permeation pressure and the current confining pressure, the creep loading still adopts the Chen's loading method, and the differential stress (σ1-σ3) of 20%, 40%, 60%, and 80% of the short-term peak strength of the rock sample is loaded, and each level of loading is maintained for 24 hours. If the damage occurs before the last level of loading, the test stops loading. If the test piece does not appear unstable damage under the last level of loading, the load is increased according to the actual situation until the rock sample is damaged. During the experiment, the permeability of the rock sample is collected by using the transient method, and the damage event of the rock sample is monitored.

[0081] The main steps of the experiment are as follows:

[0082] ①First, dry the phyllite sample and put it into the vacuum water-saturated device.

[0083] ②Rock sample installation and fixation. After the water-saturated sample is well sealed with high-performance waterproof rubber, it is put into the triaxial pressure chamber, the connection between the sample and the upper and lower water-permeable plates is sealed with waterproof tape, then sealing rings are installed at the upper and lower ends, displacement extensometers are installed, and the water inlet and outlet are connected and checked.

[0084] ③Lower the outer wall of the MTS triaxial pressure chamber, and evenly arrange 4 ACk-800 type acoustic emission probes on the outer wall. Use vaseline as a coupling agent, turn on the oil pump, and apply confining pressure to the rock sample.

[0085] ④Push the distilled water in the water inlet chamber through the piston in the seepage system to apply a certain seepage pressure to the sample. Keep the confining pressure and seepage pressure constant, apply each level of axial load, then keep the axial load constant, and use the transient method to collect the permeability of the rock sample.

[0086] ⑤Repeat step 4, record and collect permeability data according to the staged loading scheme, until the rock sample fails due to accelerated creep, and finally summarize and organize the experimental data.

[0087] S103, determine the GSI value according to the rock mass blockiness index RBI and the rock block damage index VI of the current phyllite surrounding rock, determine the strength of the current phyllite surrounding rock according to the GSI value and the Hoek-Brown criterion, and determine the geological damage degree of the current phyllite surrounding rock according to the strength.

[0088] The Hoek-Brown criterion is a method of estimating rock mass strength based on the geological conditions of the actual surrounding rock through scaling relationships. This standard is based on Hoek's experience in brittle rock failure and is based on the parabolic Mohr envelope of the Griffith theory to define the relationship between shear stress and normal stress at the onset of fracture. Hoek and Brown linked the initiation and propagation of cracks to rock failure, and through repeated tests, various parabolic curves were fitted to triaxial test data to derive their standard. Therefore, the Hoek-Brown criterion is a semi-empirical estimation method. As an empirical standard, the Hoek-Brown standard has been updated and improved several times based on experience. The expression of the generalized Hoek-Brown criterion is:

[0089]

[0090] In formula (1), σ r is the maximum principal stress at rock failure, i.e. the strength of the rock; σ3 is the minimum principal stress at rock failure; σ c is the uniaxial compressive strength of the intact rock; m b, s, a are empirical parameters, m b Reflecting the hardness degree of rock, which depends on the mineralogy, composition and granularity of the complete rock, the value range is between 0.0000001 and 25, 0.0000001 is taken for the seriously disturbed rock mass, and 25 is taken for the complete hard rock mass; s reflects the broken degree of the rock mass, the value range is between 0 and 1, 0 is taken for the completely broken rock mass, and 1 is taken for the complete rock mass; a is a coefficient related to the quality of the rock mass, for the good quality rock mass, because the rock particles are tightly embedded, thus the strength characteristics are mainly controlled by the rock particle strength, at this time, the narrow-sense Hoek-Brown empirical strength criterion is more suitable, and a=0.5 can be taken; for the poor quality rock mass, because the shear action or weathering action makes the embedding between rock blocks loose, resulting in the loss of the tensile strength of the rock mass, that is, the cohesion C=0, if there is no confining pressure limit, the rock mass will collapse, at this time, a should take other values. The expression of each coefficient in formula (3-1) is as follows:

[0091]

[0092]

[0093]

[0094]

[0095] m i is a curve fitting parameter obtained from the triaxial test of the complete rock; the parameter m b is a reduction value of m i , which explains the strength reduction effect of the rock mass condition defined by GSI; D is a disturbance factor, D=0 is taken for the undisturbed rock mass, and D=1 is taken for the completely disturbed rock mass. E.Hoek and E.J.Brown further deduced the estimated values of the related mechanical parameters of the rock mass according to formula (3-1):

[0096]

[0097]

[0098]

[0099] It can be seen from the above formula that the GSI value is the key to determine the mechanical parameters of the rock mass in the Hoek-Brown strength criterion, and the rock mass strength is usually determined by the rock mass structure and the rock block strength.

[0100] Therefore, in the embodiment of the application, the rock mass block index RBI (rock mass block index) and the rock block damage index VI (vulnerability index) are introduced to quantify the GSI value of the large deformation surrounding rock.

[0101] Further based on the GSI and Hoek-Brown criterion, the strength of the surrounding rock is obtained, and further based on the strength of the surrounding rock and the short-term load peak strength of the indoor complete rock, the geological damage degree of the current phyllite surrounding rock is obtained.

[0102] In the embodiment of the present application, the meaning of the geological damage degree of the surrounding rock is no longer limited to representing the actual total number of cracks of the rock mass, but includes the sum of various factors that cause deterioration of the strength of the rock mass, including factors such as structural planes and weathering degree, so the rock mass can be equivalent to a rock that has already undergone creep damage, and the strength of the rock mass after various geological factors on the rock strength cause deterioration is the strength of the rock mass, and these deterioration factors are collectively referred to as the geological damage degree of the rock mass.

[0103] In S104, according to the results of the triaxial creep experiment of saturated phyllite under seepage-stress conditions, the upper limit value of the cracking damage of the phyllite surrounding rock under the current seepage pressure and the current confining pressure is determined by fitting.

[0104] In the embodiment of the present application, the phyllite creep damage constitutive equation is reasonably simplified and applied. In the embodiment of the present application, based on the related formula derivation and verification, the three-dimensional creep damage constitutive equation under seepage-stress conditions is proposed as follows:

[0105]

[0106] The undetermined coefficients contained in formula (4-1) are K, P, D * , G0, G1, η1, η2, η3, M, H, wherein P represents the seepage pressure; D represents the effective damage amount, which is affected by seepage, and if there is no seepage condition, D * = 0; α represents the load level strength parameter. The creep constitutive equation of the rock can be divided into four parts:

[0107] (1) Instantaneous elastic strain: The instantaneous elastic deformation of the rock is mainly related to its own elastic modulus and the effective stress it receives, and is generally the initial value of the creep curve, corresponding to the first and second terms of formula (4-1).

[0108] (2) Attenuation creep: related to its own viscoelastic modulus, viscoelastic coefficient, and deviatoric stress it receives, the strain growth curve is an upper convex curve with decreasing slope, corresponding to the third term of formula (4-1).

[0109] (3) Cracking (constant speed) damage creep: related to the deviatoric stress it receives, its own viscosity coefficient, and the cracking damage degree, the strain growth curve is a linear function, corresponding to the fourth term of formula (4-1).

[0110] (4) Accelerated damage creep: related to the deviatoric stress, viscous coefficient and accelerated damage degree, the strain growth curve is a convex curve with increasing slope, which can be characterized by an exponential function, corresponding to the fifth term of equation (4-1).

[0111] In addition, the strength of rock material deteriorates according to the damage evolution law, and when the rock strength decreases, the creep strain increases accordingly, so the creep strain law is highly positively correlated with the damage evolution law, and the strain can be approximately characterized by a damage function. After combining and arranging the parameters in equation (4-1), we get:

[0112]

[0113] In equation (4-2), σ e is the effective stress, S 11 is the effective deviatoric stress, D * represents the effective damage quantity, which is determined by indoor seepage test, and if there is no seepage condition, D * = 0; σ s2 represents the long-term strength of rock; A, B, C, F, M, N are all undetermined parameters, which can be determined by indoor creep test, A and B are determined by the instantaneous elastic stage, C and F are determined by the decay creep strain curve, M is determined by the constant speed creep strain curve, and N is determined by the accelerated damage creep strain curve; D n is the initial damage function, which is a linear evolution law, and is set as D n = kt, k is a damage parameter affected by the ratio of deviatoric stress to short-term peak strength; D g is the accelerated damage function, which is a power function evolution law, and is set as D g = mt n , m and n are accelerated damage parameters; the damage evolution law curve is obtained by indoor acoustic emission test, and the damage parameters are obtained by fitting, thus simplifying the 10 creep parameters in equation (4-1) to 6, greatly reducing the complexity of the original creep damage constitutive. The test results of saturated phyllite under seepage action are fitted with the creep damage parameters in equation (4-2).

[0114] When the rock constant speed creep damage D n reaches the maximum, it is the critical point from stable to unstable creep, which can be obtained by fitting the results of indoor test. According to the indoor test, the maximum initial damage of saturated phyllite and the corresponding values of confining pressure and permeability pressure are summarized in Table 1.

[0115] Table 1, the maximum initial damage of saturated phyllite and the corresponding values of confining pressure and permeability pressure

[0116]

[0117] Since the creep crack initiation damage of phyllite is a linear function, with the ratio of seepage pressure to saturated peak strength P / σ0 and the ratio of confining pressure to saturated peak strength σ3 / σ0 as independent variables, the relationship can be obtained by linear regression analysis in origin software as follows:

[0118]

[0119] The upper limit value of crack initiation damage under the conditions of seepage pressure P and confining pressure σ3 is obtained by the full creep test from deformation to failure of the indoor intact phyllite, and the geological damage degree of phyllite surrounding rock can be estimated by combining the measured confining pressure and seepage pressure, and then compared with Compared with the crack initiation damage upper limit value, the creep of the rock mass at this time is judged whether it is in an unstable stage, and on this basis, early identification of whether the surrounding rock has large deformation is carried out.

[0120] S105, in the case that the geological damage degree is not less than the crack initiation damage upper limit value, it is judged that the current phyllite surrounding rock has a large deformation risk.

[0121] In the embodiment of the present application, by comparing the geological damage degree D of the surrounding rock with the maximum crack initiation damage, the creep stage of the surrounding rock is preliminarily judged, so that the preliminary identification of whether the surrounding rock has large deformation is carried out.

[0122] Referring to Figure 2 , a flow chart of a surrounding rock large deformation risk discrimination method of a phyllite tunnel is shown, and the surrounding rock large deformation risk discrimination method of the phyllite tunnel provided by the embodiment of the present application can include the following steps:

[0123] S201, for unexcavated phyllite surrounding rock, an advanced drill hole and a monitoring point are arranged on the working face.

[0124] The advanced drill hole corresponds to the position of the monitoring point, the monitoring point is used to measure the current seepage pressure and current confining pressure of the current phyllite surrounding rock, and the advanced drill hole is used to obtain the engineering geological characteristics of the current phyllite surrounding rock.

[0125] S202, the current seepage pressure and current confining pressure of the current phyllite surrounding rock are determined.

[0126] In the embodiment of the present application, the calculation method of the lining external water pressure in the “Hydraulic Tunnel Design Specification DL / T5195-2004” is as follows: P=βP0=βγΔH.

[0127] Wherein, P is the external water pressure acting on the lining, that is, the osmotic pressure; β is the groundwater pressure correction coefficient; P0 is the static water pressure generated by the groundwater level; γ is the groundwater density; ΔH is the difference between the groundwater level height and the calculation point height, and the groundwater pressure correction coefficient β is valued according to the following table 2:

[0128] Table 2, groundwater pressure correction coefficient value table

[0129]

[0130]

[0131] S203, obtaining the rock mass blockiness index RBI and the rock mass damage index VI of the current phyllite surrounding rock according to the engineering geological characteristics of the current phyllite surrounding rock.

[0132] The step S203 is similar to the above-mentioned step S102, and the embodiment of the present application will not be described here.

[0133] S204, determining the GSI value according to the rock mass blockiness index RBI and the rock mass damage index VI of the current phyllite surrounding rock, determining the strength of the current phyllite surrounding rock according to the GSI value and the Hoek-Brown criterion, and determining the geological damage degree of the current phyllite surrounding rock according to the strength.

[0134] Specifically, in the embodiment of the present application, the step S204 comprises:

[0135] S2041, measuring the length of the drilled core of the current phyllite surrounding rock collected.

[0136] S2042, defining the percentage of the drilled core with a measured length of 3-10 cm, 10-30 cm, 30-50 cm, 50-100 cm and more than 100 cm as a weight, multiplying the weight by a corresponding coefficient and summing up to obtain the rock mass blockiness index RBI of the current phyllite surrounding rock.

[0137] The most commonly used index to describe the structure characteristics and quality of rock mass is the RQD index of rock mass, which is defined as the percentage of the total length of the complete core piece with a length of more than 0.1 m relative to the selected evaluation drill core length. Obviously, only calculating the percentage of the length of the core with a length of more than 10 cm in the length of the entire drill hole is not accurate enough for the description of a multi-jointed rock mass. For example, the core with a length of more than 10 cm accounts for 100% in a certain drill hole, and the core with a length of more than 50 cm accounts for 100% in another drill hole, and the two rock masses of the same lithology are obviously different in structure.

[0138] Rock mass blockiness index (RBI) can comprehensively represent the size of rock mass blockiness, structure type and the combination relationship of structure. In RBI index, the percentage of drill core with the length of 3-10 cm, 10-30 cm, 30-50 cm, 50-100 cm and >100 cm is defined as weight, and then the weight is multiplied by the corresponding coefficient to obtain RBI value:

[0139] RBI = 3C r3 + 10C r10 + 30C r30 + 50C r50 + 100C r100 (42-1)

[0140] In formula (42-1), C, C, C, C and C are respectively the core yield rate with the length of 3-10 cm, 10-30 cm, 30-50 cm, 50-100 cm and >100 cm, expressed by percentage, and regarded as weight. In combination with the description of rock mass structure on site, RBI corresponds to the expression of rock mass structure, as shown in the following table 3:

[0141] Table 3, RBI description of rock mass structure

[0142]

[0143]

[0144] S2043, according to the results of saturated phyllite triaxial creep experiment under seepage-stress condition, the rock block damage index VI of phyllite surrounding rock under the current seepage pressure and the current confining pressure is determined.

[0145] Specifically, step S2043 includes:

[0146] S20431, through stress intensity ratio, combined with the results of saturated phyllite triaxial creep experiment under seepage-stress condition, the crack damage calculation value table corresponding to different stress intensity ratios under different confining pressures is obtained.

[0147] S20432, taking stress intensity ratio and the ratio of confining pressure to peak strength σ3 / σ0 as independent variables, and taking crack damage as dependent variable, linear regression analysis is carried out to obtain the corresponding relationship between stress intensity ratio, the ratio of confining pressure to peak strength and crack damage:

[0148] S20433, according to the corresponding relationship and the current stress intensity ratio σ / σ0 and the current confining pressure intensity ratio σ3 / σ0, the current phyllite damage index VI0 is obtained.

[0149] S20434, the groundwater correction coefficient λ is used to correct the phyllite damage index VI0 to obtain the rock block damage index under seepage: VI = λVI0.

[0150] Wherein, the groundwater correction coefficient λ is obtained by fitting the damage amount of the indoor seepage creep test and the triaxial creep damage amount: λ = 0.00656P 2 +1.10818; wherein, P represents the current phyllite surrounding rock current osmotic pressure; σ3 represents the current phyllite surrounding rock current confining pressure; σ0 represents the saturated peak strength of the phyllite surrounding rock, and σ represents the stress of the current phyllite surrounding rock.

[0151] In the embodiment of the application, the stress intensity ratio Combined with the saturated phyllite triaxial creep test results under seepage-stress conditions, table 4 is obtained:

[0152] Table 4, the rock damage calculation value table corresponding to each level of stress intensity ratio under different confining pressures

[0153]

[0154] The stress intensity ratio σ / σ0 and the ratio of confining pressure to peak strength σ3 / σ0 are taken as independent variables, and the cracking damage is taken as dependent variable, and the data in the table are subjected to linear regression analysis, and the following is obtained:

[0155]

[0156] The values of each level of stress intensity ratio σ / σ0 and each level of confining pressure intensity ratio σ3 / σ0 are substituted into formula 433-1, and σ0 plays a role in eliminating dimension, and the uniaxial compressive strength of the phyllite is uniformly taken as 39.12 MPa, and the phyllite damage index VI0 table is obtained, as shown in table 5, and the damage index VI0 represents the maximum damage amount that can be reached by the rock under the condition of the stress intensity ratio and the confining pressure.

[0157] Table 5, phyllite damage index VI0 table

[0158]

[0159] For the creep cracking damage of the phyllite under the seepage condition, the groundwater correction coefficient λ is considered to correct the rock damage index VI0, and the value is based on the damage amount D * (As dependent variable) and the triaxial creep damage amount D (as independent variable) are fitted (as shown in table 6), and the fitting relationship is D * = λD.

[0160] Table 6, groundwater correction coefficient λ fitting table

[0161]

[0162]

[0163] Since the effective damage amount is a quadratic function of the osmotic pressure, the groundwater damage correction coefficient λ is related to the osmotic pressure P 2 The relationship is fitted as: λ = 0.00656P 2 +1.10818.

[0164] In the embodiment of the present application, the osmotic pressure P value can be estimated according to the seepage condition of the current phyllite surrounding rock, and then substituted into the above formula to obtain the correction coefficient of the damage of the groundwater, and the rock damage index VI0 obtained by the stress intensity ratio and the confining pressure is corrected to obtain the rock damage index VI under seepage.

[0165] S2044, determining the GSI value according to the rock mass block index RBI and the rock damage index VI.

[0166] In the embodiment of the present application, the traditional method based on the Hoek-Brown criterion geological strength index only provides an empirical GSI table, and the quantitative research on the GSI table in the related art is used as a reference, and the rock mass structure RBI index value and the rock damage index VI index value of the phyllite surrounding rock are integrated to develop a phyllite geological strength GSI quantitative table:

[0167]

[0168] Specifically, in the embodiment of the present application, the use method of the table is as follows: for example, when VI is 0.275 and RBI is 9.7 (as indicated by the dashed line in the table), draw a horizontal and vertical straight line in the corresponding interval to obtain the intersection point in the table between 40 and 45, and then linearly interpolate between 40 and 45 to obtain the GSI value as 41.

[0169] S2045, obtaining the strength of the current phyllite surrounding rock according to the Hoek-Brown criterion and the GSI value.

[0170] S2046, determining the geological damage degree of the current phyllite surrounding rock according to the strength of the current phyllite surrounding rock and the short-term load peak strength of the intact phyllite, wherein the short-term load peak strength of the intact phyllite is obtained according to the saturated phyllite triaxial creep experiment under seepage-stress conditions.

[0171] In the embodiment of the present application, the rock mass block index coefficient RBI (rock-mass block index) and the rock damage index VI (Vulnerability index) are introduced to quantify the GSI value of the large deformation surrounding rock.

[0172] Based on the GSI and Hoek-Brown criteria, the strength of the surrounding rock is obtained, and based on the strength of the surrounding rock and the short-term load peak strength of the intact rock in the laboratory, the geological damage degree of the current phyllite surrounding rock is obtained.

[0173] In the embodiment of the present application, the meaning of the geological damage degree of the surrounding rock is no longer limited to representing the actual total number of cracks of the rock mass, but includes the sum of all factors that cause degradation of the strength of the rock mass, including factors such as structural planes and weathering degree, so the rock mass can be equivalent to a rock that has already undergone creep damage. After various geological factors on site cause degradation of the strength of the rock, it is the strength of the rock mass, and these degradation factors are collectively referred to as the geological damage degree of the rock mass.

[0174] S205, according to the triaxial creep test results of saturated phyllite under seepage-stress conditions, the upper limit value of the cracking damage of the phyllite surrounding rock under the current seepage pressure and the current confining pressure is determined by fitting.

[0175] Specifically, step S205 includes:

[0176] S2051, according to the triaxial creep test results of saturated phyllite under seepage-stress conditions, the corresponding relationship between the upper limit value of the cracking damage of the phyllite and the confining pressure and the seepage pressure is obtained by fitting.

[0177] S2052, according to the corresponding relationship, the upper limit value of the cracking damage under the current seepage pressure and the current confining pressure is determined.

[0178] S206, in the case where the geological damage degree is not less than the upper limit value of the cracking damage, it is determined that the current phyllite surrounding rock has a large deformation risk.

[0179] For ease of understanding, the following will further explain a phyllite tunnel surrounding rock large deformation risk discrimination method provided by the embodiment of the present application through a specific embodiment. It can be understood that the embodiment is only an example:

[0180] The large deformation mileage section of the Shiziping tunnel project of the Wenchuan-Markang Expressway is taken as an example for analysis. The tunnel is a super-long left-right split tunnel project (the left tunnel is 5695m long and the right tunnel is 5672m long), and large deformation occurs in multiple sections, which causes circumferential cracking at multiple points along the initial support arch, and causes local cracking and peeling of the sidewall and the tunnel top.

[0181] The surrounding rock near ZK145+630 of the Shiziping tunnel large deformation mileage section is taken for analysis. The overburden layer near the tunnel face of this mileage section is shown in Figure 3 , Figure 3 The geological profile near the tunnel face of ZK145+630 is shown; the lithology of the tunnel face is shown in Figure 4 ,Figure 4 The geological sketch of the face at K143+630 is shown, which is obtained from the field survey report. The surrounding rock is mainly composed of phyllic phyllite with partial carbonaceous phyllite, which is V-class surrounding rock. The rock mass is in layered structure, with a buried depth of 746 m. The specific gravity of the phyllite is γ = 22.54 kN / m 3 The overlying vertical pressure is γH = 16814 kN / m 2 = 16.81 MPa.

[0182] When the surrounding rock is not excavated, the positions of the advanced geological drill holes arranged on the face and the distribution of the monitoring points after excavation are as follows Figure 5 , Figure 5 The monitoring points and the arrangement points of the advanced drill holes in the tunnel (ZK145+630) are shown. The length of the rock core collected on site (the depth of the advanced drill hole is 30 m, and the part near the face with large disturbance is removed, and the complete rock core in the rear part is taken) is measured, and the rock mass RBI value at each position is calculated (as shown in Table 7 below). After the surrounding rock is excavated, the deformation of the surrounding rock is monitored, and the monitoring contents include: data1-wall convergence deformation; data2-right haunch settlement; data3-crown settlement; data4-left haunch settlement; and data5-haunch convergence deformation.

[0183] Table 7, RBI value of each monitoring point

[0184] Monitoring point RBI value 1 6.763 2 5.626 3 3.748 4 2.8 5 4.331

[0185] The rock samples at each monitoring point of the ZK145+630 section are obtained. According to the in-situ stress test data, the horizontal tectonic stress is about 15 MPa,

[0186] Taking monitoring point 4 as an example, according to the field survey, the rock mass blockiness index RBI of the rock core of the geological drill hole at the monitoring point 4 is about 2.8, the stress intensity ratio σ / σ0 = 0.369, and the damage index VI0 obtained by interpolation according to Tables 6-7 is 0.152. The difference in underground water level is 40 m (1770.52-1730.52 = 40 m), the initial permeation pressure P0 = γH = 10*40 = 400 KPa is calculated, the underground water pressure correction coefficient β is taken as 0.4, the permeation pressure of the underground water in the tunnel surrounding pressure is about 160 KPa, and the damage index VI = λVI0 = 0.170 is obtained by substituting into formula 42-1, the GSI = 18.46 is obtained by looking up the GSI quantification table of phyllite geology, the Hoek-Brown constant m i of the complete phyllite rock is 10, the uniaxial compressive strength σ c of the saturated state is 33.46 MPa. According to formula (3-5), σ 3max = σ c= 8.36 MPa, and according to formulas (3-2) to (3-4), m b = 0.737, s = 0.0003, and a = 0.527, and according to formulas (3-1) and (3-8), the strength σ r = 16.33 MPa. The basic mechanical parameters of the surrounding rock of each point are shown in Table 8.

[0187] Table 8, basic parameters of surrounding rock of each point

[0188]

[0189] The peak strength of the phyllite under the action of short-term load with a confining pressure of 15 MPa is taken as the undamaged strength (40.61 MPa), and the geological damage degrees of the rock mass of each point are calculated and shown in Table 9.

[0190] Table 9, geological damage degrees of surrounding rock of each point

[0191]

[0192] According to formula (4-3), the maximum cracking damage of the phyllite of the section is calculated as: (D n ) max = 0.07077 * 0.16 / 40.61 + 38.707 * 15 / 40.61 - 13.798 = 0.575

[0193] In Table 9, only the geological damage degree of the surrounding rock at the fourth point is 0.598, which is greater than the maximum cracking damage of the phyllite 0.575, indicating that the surrounding rock near the point is in an accelerated damage stage after excavation, the creep rate will increase, and it is preliminarily judged to be in an unstable state, with a large deformation risk, which needs special attention. After the ZK145+630 working face is excavated, the deformation monitoring data of the surrounding rock of each monitoring point are shown in Figure 6 , Figure 6 Fig. 4 shows the monitoring values of the settlement deformation of each monitoring point of the ZK145+630 section after excavation. The results show that the settlement deformation of the monitoring point at the left haunch of the tunnel is in a faster and faster trend, which is consistent with the preliminary judgment.

[0194] The method provided by the embodiment of the application is a preliminary identification according to the geological damage degree represented by the engineering geological characteristics of unexcavated surrounding rock, and for whether the surrounding rock will have large deformation after excavation, further calculation and prediction analysis can be performed in combination with the field monitoring data.

[0195] Based on the same inventive concept, the embodiment of the application provides a surrounding rock large deformation risk identification device for a phyllite tunnel, which refers to Figure 7 , Figure 7 Fig. 1 is a schematic diagram of a surrounding rock large deformation risk identification device for a phyllite tunnel provided by the embodiment of the application. As shown inFigure 7 The device comprises:

[0196] The first determining module 701 is configured to determine a current permeation pressure and a current confining pressure of the current phyllite surrounding rock.

[0197] The second determining module 702 is configured to obtain a rock mass blockiness index RBI and a rock block damage index VI of the current phyllite surrounding rock according to engineering geological features of the current phyllite surrounding rock, the engineering geological features being obtained by drilling and sampling the current phyllite surrounding rock.

[0198] The third determining module 703 is configured to determine a GSI value according to the rock mass blockiness index RBI and the rock block damage index VI of the current phyllite surrounding rock, determine a strength of the current phyllite surrounding rock according to the GSI value and Hoek-Brown criterion, and determine a geological damage degree of the current phyllite surrounding rock according to the strength.

[0199] The fourth determining module 704 is configured to determine an upper limit value of cracking damage of the phyllite surrounding rock under the current permeation pressure and the current confining pressure according to a triaxial creep experiment result of the saturated phyllite under seepage-stress conditions.

[0200] The discriminating module 705 is configured to discriminate that the current phyllite surrounding rock has a large deformation risk in a case where the geological damage degree is not less than the upper limit value of cracking damage.

[0201] Optionally, the third determining module 703 comprises:

[0202] The measuring sub-module is configured to measure a length of the collected drilling core of the current phyllite surrounding rock.

[0203] The first sub-module is configured to define percentages of drilling cores with lengths of 3-10 cm, 10-30 cm, 30-50 cm, 50-100 cm and more than 100 cm as weights, multiply the weights by corresponding coefficients and sum the results to obtain the rock mass blockiness index RBI of the current phyllite surrounding rock.

[0204] The second determining sub-module is configured to determine the rock block damage index VI of the phyllite surrounding rock under the current permeation pressure and the current confining pressure according to a triaxial creep experiment result of the saturated phyllite under seepage-stress conditions.

[0205] The third determining sub-module is configured to determine the GSI value according to the rock mass blockiness index RBI and the rock block damage index VI.

[0206] The fourth determining sub-module is configured to obtain the strength of the current phyllite surrounding rock according to the Hoek-Brown criterion and the GSI value.

[0207] A fifth determining sub-module is configured to determine the geological damage degree of the current phyllite surrounding rock according to the strength of the current phyllite surrounding rock and a short-term load peak strength of the intact phyllite, wherein the short-term load peak strength of the intact phyllite is obtained according to a triaxial creep experiment of saturated phyllite under seepage-stress conditions.

[0208] Optionally, the second determining sub-module is specifically configured to:

[0209] A table of crack damage calculation values corresponding to stress intensity ratios at different confining pressures is obtained by combining the stress intensity ratio with the triaxial creep experiment results of saturated phyllite under seepage-stress conditions.

[0210] A linear regression analysis is performed on the stress intensity ratio and the ratio of the confining pressure to the peak strength σ3 / σ0 as independent variables and the crack damage as a dependent variable, to obtain a corresponding relationship between the stress intensity ratio, the ratio of the confining pressure to the peak strength, and the crack damage:

[0211] A current phyllite damage index VI0 is obtained according to the corresponding relationship and the current stress intensity ratio σ / σ0 and the current confining pressure intensity ratio σ3 / σ0.

[0212] The phyllite damage index VI0 is corrected by using a groundwater correction coefficient λ to obtain a rock mass damage index under seepage: VI = λVI0.

[0213] The groundwater correction coefficient λ is fitted based on the damage amount of the indoor seepage creep test and the triaxial creep damage amount: λ = 0.00656P 2 + 1.10818.

[0214] P represents the current seepage pressure of the current phyllite surrounding rock, σ3 represents the current confining pressure of the current phyllite surrounding rock, σ0 represents the peak strength of the phyllite surrounding rock in water, and σ represents the stress of the current phyllite surrounding rock.

[0215] Optionally, the fourth determining module is specifically configured to:

[0216] A corresponding relationship between the upper limit of the crack damage of the phyllite and the confining pressure and the seepage pressure is fitted according to the triaxial creep experiment results of saturated phyllite under seepage-stress conditions.

[0217] According to the corresponding relationship, the upper limit of the crack damage under the current seepage pressure and the current confining pressure conditions is determined.

[0218] Optionally, the apparatus further comprises:

[0219] A layout module is configured to, for unexcavated phyllite surrounding rock, layout an advanced borehole and a monitoring point on a working face.

[0220] The advanced drill hole corresponds to the monitoring point position, the monitoring point is used for measuring the current phyllite surrounding rock current permeation pressure and current confining pressure, and the advanced drill hole is used for obtaining the engineering geological characteristics of the current phyllite surrounding rock.

[0221] For the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts refer to the part of the method embodiment.

[0222] Based on the same inventive concept, the embodiments of the present application provide a computer readable storage medium, which stores a computer program, and the program is executed by a processor to realize the steps in the surrounding rock large deformation risk discrimination method of the phyllite tunnel of any one of the above-mentioned embodiments.

[0223] Based on the same inventive concept, the embodiments of the present application provide an electronic device, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor realizes the steps in the surrounding rock large deformation risk discrimination method of the phyllite tunnel of any one of the above-mentioned embodiments when executed.

[0224] Each embodiment in the specification is described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same and similar parts between each embodiment can be referred to each other.

[0225] Those skilled in the art should understand that the embodiments of the embodiments of the present application can be provided as a method, device or computer program product. Therefore, the embodiments of the present application can adopt a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware aspects. Moreover, the embodiments of the present application can adopt the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) containing computer usable program code.

[0226] The embodiments of the present application are described with reference to the flowcharts and / or block diagrams according to the method, terminal device (system) and computer program product of the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram and the combination of the flows and / or blocks in the flowchart and / or block diagram can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing terminal device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal device produce a machine that implements the functions specified in the flowchart and / or block diagram. Figure 1 The device for realizing the functions specified in one flow or multiple flows and / or blocks Figure 1 The device for realizing the functions specified in one flow or multiple flows and / or blocks

[0227] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the flow Figure 1 one or more flows and / or blocks Figure 1 one or more blocks or multiple blocks.

[0228] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the flow Figure 1 one or more flows and / or blocks Figure 1 one or more blocks or multiple blocks.

[0229] While preferred embodiments of the application have been described, those skilled in the art will recognize that additional modifications and changes can be made thereto without departing from the scope of the application. Accordingly, the appended claims are intended to cover all such modifications and changes as fall within the scope of the application.

[0230] Finally, it should be noted that the terms "first", "second", and the like, herein do not denote any order, quantity, combination, or importance, but rather are used to distinguish one element from another, and are not intended to denote a particular order, quantity, combination, or importance of, or between, the elements so designated. Also, the use of the terms "including", "containing", or "comprising" and variations thereof, is meant to encompass the inclusion of zero or more elements, steps, or components, and is not meant to exclude the addition of other elements, steps, or components, or the performance of further additions, whether optional or required. Without further limitation, an element, step, or component preceded by "comprising" does not exclude the addition of more elements, steps, or components, whether optional or required.

[0231] The above provides a phyllite tunnel surrounding rock large deformation risk discrimination method, device and product, and the principle and implementation mode of the present application are described by using specific examples. The above embodiment is only used to help understand the method and core idea of the present application. Meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range can be changed. Therefore, the content of the specification should not be understood as limiting the present application.

Claims

1. A method for judging the risk of large deformation of surrounding rock of a phyllite tunnel, characterized in that, The method comprises: determining the current permeability pressure and the current confining pressure of the current phyllite surrounding rock; obtaining the rock mass blockiness index RBI and the rock block damage index VI of the current phyllite surrounding rock according to the engineering geological characteristics of the current phyllite surrounding rock, wherein the engineering geological characteristics are obtained by drilling sampling on the current phyllite surrounding rock; determining the GSI value according to the rock mass blockiness index RBI and the rock block damage index VI of the current phyllite surrounding rock, determining the strength of the current phyllite surrounding rock according to the GSI value and the Hoek-Brown criterion, and determining the geological damage degree of the current phyllite surrounding rock according to the strength; determining the upper limit value of the cracking damage of the phyllite surrounding rock under the current permeability pressure and the current confining pressure according to the triaxial creep test results of the saturated phyllite under the seepage-stress condition; in the case that the geological damage degree is not less than the upper limit value of the cracking damage, determining whether the current phyllite surrounding rock has a large deformation risk; wherein, determining the GSI value according to the rock mass blockiness index RBI and the rock block damage index VI of the current phyllite surrounding rock, determining the strength of the current phyllite surrounding rock according to the GSI value and the Hoek-Brown criterion, and determining the geological damage degree of the current phyllite surrounding rock according to the strength, comprises: measuring the length of the drilled core of the collected current phyllite surrounding rock; defining the percentage of the drilled core with the measured length of 3-10 cm, 10-30 cm, 30-50 cm, 50-100 cm and more than 100 cm as a weight, multiplying the weight by a corresponding coefficient and summing up to obtain the rock mass blockiness index RBI of the current phyllite surrounding rock; determining the rock block damage index VI of the phyllite surrounding rock under the current permeability pressure and the current confining pressure according to the triaxial creep test results of the saturated phyllite under the seepage-stress condition; determining the GSI value according to the rock mass blockiness index RBI and the rock block damage index VI; obtaining the strength of the current phyllite surrounding rock according to the Hoek-Brown criterion and the GSI value; determining the geological damage degree of the current phyllite surrounding rock according to the strength of the current phyllite surrounding rock and the short-term load peak strength of the intact phyllite, wherein the short-term load peak strength of the intact phyllite is obtained according to the triaxial creep test of the saturated phyllite under the seepage-stress condition.

2. The method of claim 1, wherein, determining the rock block damage index VI of the phyllite surrounding rock under the current permeability pressure and the current confining pressure according to the triaxial creep test results of the saturated phyllite under the seepage-stress condition, comprises: obtaining a cracking damage calculation value table corresponding to different stress intensity ratios under different confining pressures by the stress intensity ratio and the triaxial creep test results of the saturated phyllite under the seepage-stress condition; The ratio of the stress intensity ratio and the confining pressure to the peak strength As the independent variable, the cracking damage as the dependent variable, linear regression analysis, the ratio of the stress intensity ratio and the confining pressure to the peak strength, and the corresponding relationship between the cracking damage: ; According to the correspondence and the current stress intensity ratio and the current confining pressure intensity ratio obtain the current shale damage index VI0; correcting the phyllite damage index VI0 by using the groundwater correction coefficient λ to obtain the rock block damage index VI under seepage: VI=λVI0; The groundwater correction coefficient λ is obtained by fitting the damage amount of the indoor seepage creep test and the triaxial creep damage amount. ​ wherein P represents the current phyllite surrounding rock current osmotic pressure; represents the current phyllite surrounding rock current confining pressure; represents the saturated peak strength of the phyllite surrounding rock, represents the current phyllite surrounding rock stress.

3. The method of claim 1, wherein, determining the upper limit value of the cracking damage of the phyllite surrounding rock under the current permeability pressure and the current confining pressure according to the triaxial creep test results of the saturated phyllite under the seepage-stress condition, comprises: According to the triaxial creep experiment results of the saturated phyllite under the seepage-stress condition, a corresponding relationship between the cracking damage upper limit value of the phyllite and the confining pressure and the seepage pressure is fitted; According to the corresponding relationship, the cracking damage upper limit value under the current seepage pressure and the current confining pressure is determined.

4. The method of claim 1, wherein, The method further comprises: For the unexcavated phyllite surrounding rock, an advanced drill hole and a monitoring point are arranged on the working face; The advanced drill hole corresponds to the position of the monitoring point, the monitoring point is used to measure the current seepage pressure and the current confining pressure of the current phyllite surrounding rock, and the advanced drill hole is used to obtain the engineering geological characteristics of the current phyllite surrounding rock.

5. A device for judging a risk of large deformation of a surrounding rock of a phyllite tunnel, characterized by, The device comprises: A first determination module is configured to determine the current seepage pressure and the current confining pressure of the current phyllite surrounding rock; A second determination module is configured to obtain the rock mass blockiness index RBI and the rock block damage index VI of the current phyllite surrounding rock according to the engineering geological characteristics of the current phyllite surrounding rock, wherein the engineering geological characteristics are obtained by drilling sampling on the current phyllite surrounding rock; A third determination module is configured to determine the GSI value according to the rock mass blockiness index RBI and the rock block damage index VI of the current phyllite surrounding rock, determine the strength of the current phyllite surrounding rock according to the GSI value and the Hoek-Brown criterion, and determine the geological damage degree of the current phyllite surrounding rock according to the strength; A fourth determination module is configured to determine the cracking damage upper limit value of the phyllite surrounding rock under the current seepage pressure and the current confining pressure according to the triaxial creep experiment results of the saturated phyllite under the seepage-stress condition; A discrimination module is configured to discriminate that the current phyllite surrounding rock has a large deformation risk when the geological damage degree is not less than the cracking damage upper limit value; The third determination module comprises: A measurement submodule is configured to measure the length of the collected drill core of the current phyllite surrounding rock; A first submodule is configured to define the percentage of the drill core with a measured length of 3-10 cm, 10-30 cm, 30-50 cm, 50-100 cm and greater than 100 cm as a weight, multiply the weight by a corresponding coefficient and sum the results to obtain the rock mass blockiness index RBI of the current phyllite surrounding rock; A second determination submodule is configured to determine the rock block damage index VI of the phyllite surrounding rock under the current seepage pressure and the current confining pressure according to the triaxial creep experiment results of the saturated phyllite under the seepage-stress condition; A third determination submodule is configured to determine the GSI value according to the rock mass blockiness index RBI and the rock block damage index VI; A fourth determination submodule is configured to obtain the strength of the current phyllite surrounding rock according to the Hoek-Brown criterion and the GSI value; A fifth determination submodule is configured to determine the geological damage degree of the current phyllite surrounding rock according to the strength of the current phyllite surrounding rock and the short-term load peak strength of the intact phyllite, wherein the short-term load peak strength of the intact phyllite is obtained according to the triaxial creep experiment results of the saturated phyllite under the seepage-stress condition.

6. The apparatus of claim 5, wherein, The second determination submodule is specifically configured to: Through the stress intensity ratio, combined with the saturated phyllite triaxial creep test results under seepage-stress conditions, a table of the calculated values of the cracking damage corresponding to the stress intensity ratio of each level under different confining pressures is obtained; The ratio of the stress intensity ratio and the confining pressure to the peak strength As the independent variable, the cracking damage as the dependent variable, linear regression analysis, the ratio of the stress intensity ratio and the confining pressure to the peak strength, and the corresponding relationship between the cracking damage: ; According to the correspondence and the current stress intensity ratio and the current confining pressure intensity ratio obtain the current shale damage index VI0; The damage index VI0 of the phyllite is corrected by using a groundwater correction coefficient λ to obtain the rock mass damage index VI under seepage: VI = λVI0. The groundwater correction coefficient λ is obtained by fitting the damage amount of the indoor seepage creep test and the triaxial creep damage amount. ​ wherein P represents the current phyllite surrounding rock current osmotic pressure; represents the current phyllite surrounding rock current confining pressure; represents the saturated peak strength of the phyllite surrounding rock, represents the current phyllite surrounding rock stress.

7. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the program to realize the steps of the large deformation risk discrimination method of the surrounding rock of the phyllite tunnel according to any one of claims 1-4.

8. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to realize the steps of the large deformation risk discrimination method of the surrounding rock of the phyllite tunnel according to any one of claims 1-4.

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