The rock mass consists of rock blocks and structural planes,which can reduce its integrity and strength.Therefore,accurately obtaining the characteristics of the rock mass structural plane is a prerequisite for evalua...The rock mass consists of rock blocks and structural planes,which can reduce its integrity and strength.Therefore,accurately obtaining the characteristics of the rock mass structural plane is a prerequisite for evaluating stability and designing supports in underground engineering.Currently,there are no effective testing methods for the characteristic parameters of the rock mass structural plane in underground engineering.The paper presents the digital drilling technology as a new testing method of rock mass structural planes.Flawed rock specimens with cracks of varying widths and angles were used to simulate the rock mass structural planes,and the multifunctional rock mass digital drilling test system was employed to carry out the digital drilling tests.The analysis focuses on the variation laws of drilling parameters,such as drilling pressure and drilling torque,affected by the characteristics of prefabricated cracks,and clarifies the degradation mechanism of rock equivalent compressive strength.Additionally,an identification model for the characteristic parameters of rock mass structural planes during drilling is established.The test results indicate that the average difference of the characteristics of prefabricated cracks identified by the equivalent compressive strength is 2.45and 0.82 mm,respectively.The identification model while drilling is verified to be correct due to the high identification accuracy.Based on this,a method for testing the characteristic parameters of the surrounding rock structural plane while drilling is proposed.The research offers a theoretical and methodological foundation for precise in situ identification of structural planes of the surrounding rock in underground engineering.展开更多
The instability of slope blocks occurred frequently along traffic corridor in Southeastern Tibet(TCST),which was primarily controlled by the rock mass structures.A rapid method evaluating the control effects of rock m...The instability of slope blocks occurred frequently along traffic corridor in Southeastern Tibet(TCST),which was primarily controlled by the rock mass structures.A rapid method evaluating the control effects of rock mass structures was proposed through field statistics of the slopes and rock mass structures along TCST,which combined the stereographic projection method,modified M-JCS model,and limit equilibrium theory.The instabilities of slope blocks along TCST were then evaluated rapidly,and the different control factors of instability were analyzed.Results showed that the probabilities of toppling(5.31%),planar(16.15%),and wedge(35.37%)failure of slope blocks along TCST increased sequentially.These instability modes were respectively controlled by the anti-dip joint,the joint parallel to slope surface with a dip angle smaller than the slope angle(singlejoint),and two groups of joints inclined out of the slope(double-joints).Regarding the control effects on slope block instability,the stabilization ability of doublejoints(72.7%),anti-dip joint(67.4%),and single-joint(57.6%)decreased sequentially,resulting in different probabilities of slope block instability.Additionally,nearby regional faults significantly influenced the joints,leading to spatial heterogeneity and segmental clustering in the stabilization ability provided by joints to the slope blocks.Consequently,the stability of slope blocks gradually weakened as they approached the fault zones.This paper can provide guidance and assistance for investigating the development characteristics of rock mass structures and the stability of slope blocks.展开更多
Evaluation of rock mass deformability is an important but very challenging task in the analysis and design of underground structures in rock.Although various empirical(correlation)methods have been developed for deter...Evaluation of rock mass deformability is an important but very challenging task in the analysis and design of underground structures in rock.Although various empirical(correlation)methods have been developed for determining the deformation modulus of rock masses,they come in many forms and are scattered in different sources.It is often difficult,time-consuming,or even impossible for a practitioner to find appropriate information to determine the deformation modulus of rock masses for a particular project.Therefore,this paper first provides a comprehensive review of the different empirical methods for determining the deformation modulus of rock masses.Then a comparative analysis and discussion is carried out on the accuracy and main issues of these methods.Since many of the empirical methods for determining the deformation modulus of rock masses need to use the deformation modulus of intact rock,the various empirical methods for estimating the deformation modulus of intact rock are also reviewed.In addition,this paper highlights the scale effect on rock mass deformability,the effect of confining stress on rock mass deformability,and the anisotropy of rock mass deformability.Overall this paper outlines the key aspects of rock mass deformability and provides the fundamental and essential information required for effective evaluation of rock mass deformability using the empirical methods.展开更多
The aim of this study was to analyze distribution and development of stress-stress state in structured rock specimens subject to uniaxial and biaxial loading to failure using digital speckle correlation method. Within...The aim of this study was to analyze distribution and development of stress-stress state in structured rock specimens subject to uniaxial and biaxial loading to failure using digital speckle correlation method. Within the experimental analysis of wave processes in the block-hierarchy structure of geomedia (uniaxial and biaxial compression and shearing of prismatic geomaterial specimens), the authors revealed the fact of initiation of low-frequency micro-deformation processes under slow (quasi-static) disturbances. The estimation of the deformation-wave behavior of geomaterials as the “summed” contributions made by elements of the scanned surfaces with different-oriented (in-phase and anti-phase) oscillations has been performed using the energy approach that is based on the scanning function R, analogous to the “center of mass” in the classical mechanics.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2023YFC2907600)the National Natural Science Foundation of China(Grant Nos.42277174 and 52204260).
文摘The rock mass consists of rock blocks and structural planes,which can reduce its integrity and strength.Therefore,accurately obtaining the characteristics of the rock mass structural plane is a prerequisite for evaluating stability and designing supports in underground engineering.Currently,there are no effective testing methods for the characteristic parameters of the rock mass structural plane in underground engineering.The paper presents the digital drilling technology as a new testing method of rock mass structural planes.Flawed rock specimens with cracks of varying widths and angles were used to simulate the rock mass structural planes,and the multifunctional rock mass digital drilling test system was employed to carry out the digital drilling tests.The analysis focuses on the variation laws of drilling parameters,such as drilling pressure and drilling torque,affected by the characteristics of prefabricated cracks,and clarifies the degradation mechanism of rock equivalent compressive strength.Additionally,an identification model for the characteristic parameters of rock mass structural planes during drilling is established.The test results indicate that the average difference of the characteristics of prefabricated cracks identified by the equivalent compressive strength is 2.45and 0.82 mm,respectively.The identification model while drilling is verified to be correct due to the high identification accuracy.Based on this,a method for testing the characteristic parameters of the surrounding rock structural plane while drilling is proposed.The research offers a theoretical and methodological foundation for precise in situ identification of structural planes of the surrounding rock in underground engineering.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.41941019,42177142)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(Grant NO.2019QZKK0904)the Fundamental Research Funds for the Central Universities,CHD(Grant No.300102212213).
文摘The instability of slope blocks occurred frequently along traffic corridor in Southeastern Tibet(TCST),which was primarily controlled by the rock mass structures.A rapid method evaluating the control effects of rock mass structures was proposed through field statistics of the slopes and rock mass structures along TCST,which combined the stereographic projection method,modified M-JCS model,and limit equilibrium theory.The instabilities of slope blocks along TCST were then evaluated rapidly,and the different control factors of instability were analyzed.Results showed that the probabilities of toppling(5.31%),planar(16.15%),and wedge(35.37%)failure of slope blocks along TCST increased sequentially.These instability modes were respectively controlled by the anti-dip joint,the joint parallel to slope surface with a dip angle smaller than the slope angle(singlejoint),and two groups of joints inclined out of the slope(double-joints).Regarding the control effects on slope block instability,the stabilization ability of doublejoints(72.7%),anti-dip joint(67.4%),and single-joint(57.6%)decreased sequentially,resulting in different probabilities of slope block instability.Additionally,nearby regional faults significantly influenced the joints,leading to spatial heterogeneity and segmental clustering in the stabilization ability provided by joints to the slope blocks.Consequently,the stability of slope blocks gradually weakened as they approached the fault zones.This paper can provide guidance and assistance for investigating the development characteristics of rock mass structures and the stability of slope blocks.
文摘Evaluation of rock mass deformability is an important but very challenging task in the analysis and design of underground structures in rock.Although various empirical(correlation)methods have been developed for determining the deformation modulus of rock masses,they come in many forms and are scattered in different sources.It is often difficult,time-consuming,or even impossible for a practitioner to find appropriate information to determine the deformation modulus of rock masses for a particular project.Therefore,this paper first provides a comprehensive review of the different empirical methods for determining the deformation modulus of rock masses.Then a comparative analysis and discussion is carried out on the accuracy and main issues of these methods.Since many of the empirical methods for determining the deformation modulus of rock masses need to use the deformation modulus of intact rock,the various empirical methods for estimating the deformation modulus of intact rock are also reviewed.In addition,this paper highlights the scale effect on rock mass deformability,the effect of confining stress on rock mass deformability,and the anisotropy of rock mass deformability.Overall this paper outlines the key aspects of rock mass deformability and provides the fundamental and essential information required for effective evaluation of rock mass deformability using the empirical methods.
文摘The aim of this study was to analyze distribution and development of stress-stress state in structured rock specimens subject to uniaxial and biaxial loading to failure using digital speckle correlation method. Within the experimental analysis of wave processes in the block-hierarchy structure of geomedia (uniaxial and biaxial compression and shearing of prismatic geomaterial specimens), the authors revealed the fact of initiation of low-frequency micro-deformation processes under slow (quasi-static) disturbances. The estimation of the deformation-wave behavior of geomaterials as the “summed” contributions made by elements of the scanned surfaces with different-oriented (in-phase and anti-phase) oscillations has been performed using the energy approach that is based on the scanning function R, analogous to the “center of mass” in the classical mechanics.
