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Due to the high bearing capacity and better controllability of bladder parameters, the multibladder-type inflatable anchor shows a great application prospect in the engineering construction in soft soil areas. In this study, based on a soft soil foundation pit project in Guangzhou Province, China, the multibladder-type inflatable anchor was applied to the engineering practice for the first time, and the working characteristics of the multibladder-type inflatable anchor were analyzed and discussed through field experiments. Primarily, the optimization design and experimental facility of the multibladder-type inflatable anchor were introduced in detail to realize the refinement and perfection of the anchorage technological process. Besides, the influence degrees of the bladder number, diameter, thickness, space, and length on the bearing characteristics and deformation control of the anchor were studied by using the control variable method, as well as the influencing mechanisms. Subsequently, the advantages of the multibladder-type inflatable anchor were presented by comparing its anchoring efficacy with that of the traditional grouting anchor. Ultimately, the analysis results were used to verify the reliability of the multibladder-type inflatable anchor and provide the experimental basis for its popularization and application.
Wen Xiang Peng; Ming Kai Xu; Yi Fan Chen; Bo Yuan; Zhuo Yang; Hang Lin. The Influences of Bladder Properties on the Working Performance of the Multibladder-Type Inflatable Anchor. Advances in Civil Engineering 2021, 2021, 1 -11.
AMA StyleWen Xiang Peng, Ming Kai Xu, Yi Fan Chen, Bo Yuan, Zhuo Yang, Hang Lin. The Influences of Bladder Properties on the Working Performance of the Multibladder-Type Inflatable Anchor. Advances in Civil Engineering. 2021; 2021 ():1-11.
Chicago/Turabian StyleWen Xiang Peng; Ming Kai Xu; Yi Fan Chen; Bo Yuan; Zhuo Yang; Hang Lin. 2021. "The Influences of Bladder Properties on the Working Performance of the Multibladder-Type Inflatable Anchor." Advances in Civil Engineering 2021, no. : 1-11.
Researches on the energy evolution of the key blocks is helpful to reveal the failure process of locked-segment type slope, whose stability is governed by the locked segment along the potential slip surface. In order to study the failure mechanism of the locked segment in the process of slope progressive failure due to strength attenuation, a series of stability analysis on the numerical models of locked-segment type slope were implemented to record the relationship curve between energy and strength reduction coefficient. Then, according to the variation law and characteristic of energy evolution, the failure process of the locked segment was divided into four stages: elastic stage, initial damage stage, extensive damage stage and failure stage. And the reduction coefficient corresponding to the peak of the energy evolution curve was employed to achieve landslide warning. In addition, the method to determine the safety factor of locked-segment type slope was given, and its reliability was verified by comparing with other traditional methods. Finally, the formula for calculating the initial sliding velocity was presented based on the residual strain energy which is defined as the elastic strain energy of the locked segment when the slope is unstable.
Xiangjie Yin; Hang Lin; Yifan Chen; Yi Tang; Yixian Wang; Yanlin Zhao; Weixun Yong. Stability Analysis of Slope Considering the Energy Evolution of Locked Segment. Geotechnical and Geological Engineering 2021, 1 -10.
AMA StyleXiangjie Yin, Hang Lin, Yifan Chen, Yi Tang, Yixian Wang, Yanlin Zhao, Weixun Yong. Stability Analysis of Slope Considering the Energy Evolution of Locked Segment. Geotechnical and Geological Engineering. 2021; ():1-10.
Chicago/Turabian StyleXiangjie Yin; Hang Lin; Yifan Chen; Yi Tang; Yixian Wang; Yanlin Zhao; Weixun Yong. 2021. "Stability Analysis of Slope Considering the Energy Evolution of Locked Segment." Geotechnical and Geological Engineering , no. : 1-10.
The constitutive models of rock are essentially the general depictions of the mechanical responses of rock mass under complex geological environments. Statistical distribution-based constitutive models are of great efficacy in reflecting the rock failure process and the stress–strain relation from the perspective of damage, while most of which were achieved by adopting Drucker–Prager criterion or Mohr–Coulomb criterion to characterize microelement failure. In this study, underpinned by Hoek–Brown strength criterion and damage theory, a new statistical damage constitutive model, which is simple in terms of model expression and capable of reflecting the strain softening characteristics of rock in post-peak stage, was established. First, the rock in the failure process was divided into infinite microelements including elastic part satisfying Hooke’s law and damaged part retaining residual strength. Based on strain equivalence hypothesis, the relation between rock microelement strength and damage variable was derived. By assuming the statistical law of microelement strength obeying Weibull distribution and the microelement failure conforming to Hoek–Brown criterion, the new statistical damage constitutive model based on Hoek–Brown criterion was, therefore, gained. The mathematical expressions of the corresponding model parameters were subsequently deduced in accordance with the geometric characteristics of the deviatoric stress–strain curve. Last, the existing conventional triaxial compression test data of representative rock samples under different confining stresses were employed to compare with the theoretical curves by proposed model, the consistency between which was quantified by utilizing the correlation factor evaluation method. The result indicated that the proposed model could well describe the entire stress–strain relationship of rock failure process and manifest the characteristics of rock residual strength. It is of great significance to the researches on rock damage and softening issues and rock reinforcement treatments.
Yifan Chen; Hang Lin; Yixian Wang; Shijie Xie; Yanlin Zhao; Weixun Yong. Statistical damage constitutive model based on the Hoek–Brown criterion. Archives of Civil and Mechanical Engineering 2021, 21, 1 -9.
AMA StyleYifan Chen, Hang Lin, Yixian Wang, Shijie Xie, Yanlin Zhao, Weixun Yong. Statistical damage constitutive model based on the Hoek–Brown criterion. Archives of Civil and Mechanical Engineering. 2021; 21 (3):1-9.
Chicago/Turabian StyleYifan Chen; Hang Lin; Yixian Wang; Shijie Xie; Yanlin Zhao; Weixun Yong. 2021. "Statistical damage constitutive model based on the Hoek–Brown criterion." Archives of Civil and Mechanical Engineering 21, no. 3: 1-9.
The locked section is a kind of geological structure that is commonly found in natural slopes. The instability criterion of the slope with a locked section structure is not yet studied. In accordance with the mechanical properties of this type of slope, the rock mass is divided into several rock blocks along its joint distribution, and the upper limit method of plastic limit analysis is introduced. By combining the principle of virtual work and the characteristics of the slope, a virtual speed is assigned to the slope and the locked section. In addition, the maximum elastic strain energy that can be accumulated in the locked section is calculated to derive its deformation rate and internal energy dissipation power. The virtual velocity, internal energy dissipation power, and gravity work power of the locked section and the rock slope are solved simultaneously in accordance with the Mohr–Coulomb correlation flow law. Finally, the formula for calculating the safety factor of this type of slope under shear failure mode is derived. A slope in Xikou, Sichuan, China, is taken as an example to verify the proposed model.
Yi Tang; Hang Lin; Yixian Wang; Yanlin Zhao. Rock slope stability analysis considering the effect of locked section. Bulletin of Engineering Geology and the Environment 2021, 80, 7241 -7251.
AMA StyleYi Tang, Hang Lin, Yixian Wang, Yanlin Zhao. Rock slope stability analysis considering the effect of locked section. Bulletin of Engineering Geology and the Environment. 2021; 80 (9):7241-7251.
Chicago/Turabian StyleYi Tang; Hang Lin; Yixian Wang; Yanlin Zhao. 2021. "Rock slope stability analysis considering the effect of locked section." Bulletin of Engineering Geology and the Environment 80, no. 9: 7241-7251.
The constitutive model of rock is closely connected with the mechanical properties of rock. To achieve a more accurate quantitative analysis of the mechanical properties of rock after the action of freeze-thaw cycles, it is necessary to establish the constitutive models of rock subjected to freeze-thaw cycles from the view of rock damage. Based on the assumption of rock couple damage, this study established a statistical damage constitutive model of rock subjected to freeze-thaw cycles by combining the lognormal distribution, which is commonly used in engineering reliability analysis, and the strain strength theory. Then, the coordinates and derivative at the peak of the stress-strain curve of the rock after the action of freeze-thaw cycles were obtained through experiments to solve the statistical distribution parameters με and S of the model, whereafter, the theoretical curves by the established model were compared with the experimental curves to verify the validity of it, which shows a great agreement. Finally, the sensitivity analysis of the statistical distribution parameters was implemented. The results indicate that με reflects the strength of the rock, which shows a positive relation, and S stands for the brittleness of the rock, which shows a negative relation.
Hang Lin; Linyuan Liang; Yifan Chen; Rihong Cao. A Damage Constitutive Model of Rock Subjected to Freeze-Thaw Cycles Based on Lognormal Distribution. Advances in Civil Engineering 2021, 2021, 1 -8.
AMA StyleHang Lin, Linyuan Liang, Yifan Chen, Rihong Cao. A Damage Constitutive Model of Rock Subjected to Freeze-Thaw Cycles Based on Lognormal Distribution. Advances in Civil Engineering. 2021; 2021 ():1-8.
Chicago/Turabian StyleHang Lin; Linyuan Liang; Yifan Chen; Rihong Cao. 2021. "A Damage Constitutive Model of Rock Subjected to Freeze-Thaw Cycles Based on Lognormal Distribution." Advances in Civil Engineering 2021, no. : 1-8.
The mechanical behaviors and constitutive relationships of rocks in failure process have always been the hot issues in the field of geotechnical engineering. According to the characteristics of random distribution of rock micro-element strength, based on Weibull distribution function, the improved Harris distribution function, power function and composite power function, the evolution equations of rock damage under different distribution functions were derived, and the statistical constitutive models of rock damage in the form of axial deviatoric stress–strain curve were established by combining rock damage theory and statistical strength theory. The validity comparison and analysis of these models were then implemented underpinned by traditional triaxial experimental data of sandstone in reported literature. Primarily, the theoretical curves of four damage models are all in good agreement with the experimental finding in the pre-peak stage. The curve originated from the power function model failed to describe the strain softening characteristic in the post-peak stage, and a sharp drop could be observed, while the others presented a better consistency with the data to a certain extent. Wherein, similar matching effect of curves to data based on the Weibull distribution function and the composite power function was discovered.
Hang Lin; Jingjing Feng; Rihong Cao; Shijie Xie. Comparative Analysis of Rock Damage Models Based on Different Distribution Functions. Geotechnical and Geological Engineering 2021, 1 -10.
AMA StyleHang Lin, Jingjing Feng, Rihong Cao, Shijie Xie. Comparative Analysis of Rock Damage Models Based on Different Distribution Functions. Geotechnical and Geological Engineering. 2021; ():1-10.
Chicago/Turabian StyleHang Lin; Jingjing Feng; Rihong Cao; Shijie Xie. 2021. "Comparative Analysis of Rock Damage Models Based on Different Distribution Functions." Geotechnical and Geological Engineering , no. : 1-10.
The failure criterion of rocks is a critical factor involved in reliability design and stability analysis of geotechnical engineering. In order to accurately evaluate the triaxial compressive strength of rocks under different confining pressures, a nonlinear empirical strength criterion based on Mohr-Coulomb criterion was proposed in this paper. Through the analysis of triaxial test strength of 11 types of rock materials, the feasibility and validity of proposed criterion was discussed. For a further verification, six typical strength criteria were selected, and the prediction results of each criterion and test results were statistically analyzed. The comparative comparison results show that the prediction results obtained by applying this new criterion to 97 conventional triaxial compression tests of 11 different rock materials are highly consistent with the experimental data. Statistical analysis was executed to assess the application of the new criterion and other classical criteria in predicting the failure behavior of rock. This proposed empirical criterion provides a new reference and method for the determination of triaxial compressive strength of rock materials.
Shi-Jie Xie; Hang Lin; Yi-Fan Chen; Yi-Xian Wang. A new nonlinear empirical strength criterion for rocks under conventional triaxial compression. Journal of Central South University 2021, 28, 1448 -1458.
AMA StyleShi-Jie Xie, Hang Lin, Yi-Fan Chen, Yi-Xian Wang. A new nonlinear empirical strength criterion for rocks under conventional triaxial compression. Journal of Central South University. 2021; 28 (5):1448-1458.
Chicago/Turabian StyleShi-Jie Xie; Hang Lin; Yi-Fan Chen; Yi-Xian Wang. 2021. "A new nonlinear empirical strength criterion for rocks under conventional triaxial compression." Journal of Central South University 28, no. 5: 1448-1458.
To study the damage characteristics of rock mass under multi-level creep load, damage variable D was defined based on the spatio-temporal evolution characteristics of deformation modulus E, and the Kachanov damage theory is used to describe the damage evolution, then the damage evolution equation of the rock mass under multi-level creep load is obtained. Combining the damage evolution equation with the Lemaitre strain equivalence principle, the creep damage constitutive model of rock mass under multi-level creep load considering initial damage is obtained. By comparing the results of uniaxial and triaxial tests with the calculated values of the model, the rationality, reliability, application range of the model proposed in this paper is verified. According to the results of parameter inversion, obtain the relationship between damage, stress and time. Results show that time and stress are the important factors influencing the damage of rock mass under multi-level creep loading, the damage increases with time and stress level. However, the influence of time and stress on damage has a significant stress response characteristics: under low stress, the instantaneous damage Dis caused by the instantaneous stress loading is the main reason for the damage. With the increase of the load level, the main cause of the damage gradually changes from the instantaneous loading of the stress to the creep accumulation of the damage, and the greater the initial damage, the higher the time-dependent damage DiT proportion in the global damage.
Xing Zhang; Hang Lin; Yixian Wang; Yanlin Zhao. Creep damage model of rock mass under multi-level creep load based on spatio-temporal evolution of deformation modulus. Archives of Civil and Mechanical Engineering 2021, 21, 1 -16.
AMA StyleXing Zhang, Hang Lin, Yixian Wang, Yanlin Zhao. Creep damage model of rock mass under multi-level creep load based on spatio-temporal evolution of deformation modulus. Archives of Civil and Mechanical Engineering. 2021; 21 (2):1-16.
Chicago/Turabian StyleXing Zhang; Hang Lin; Yixian Wang; Yanlin Zhao. 2021. "Creep damage model of rock mass under multi-level creep load based on spatio-temporal evolution of deformation modulus." Archives of Civil and Mechanical Engineering 21, no. 2: 1-16.
This paper investigated the relationship between the strength of fractured rock and the crack propagation process. A series of uniaxial compression tests were carried out on the rock-like material specimens with single pre-fabricated flaw. Moreover, DIC (digital image correlation) technology was utilized to monitor and analyze the failure process of specimens. The initiation of each crack was defined as a key event, and the relationship between several key events and the axial load of the specimen during the crack propagation was quantitatively analyzed. The time-sequence analysis of crack propagation was also conducted by selecting benchmark points on the both sides of major cracks. It can be found that only the wing crack propagation occurs and there is no obvious shear crack before the peak strength. When the first secondary crack initiated, the specimen reached its peak strength and the wing crack just reached its critical length. Beyond the peak strength, secondary cracks initiated and coalesced rapidly, which leads to the sudden failure of fractured rock. Therefore, the peak strength of the specimen can be assessed by taking the critical length of the steadily propagating wing crack as the condition which determines whether the specimen reaches the peak strength. Furthermore, the discrete element numerical simulation was also implemented to confirm the experimental results.
Hengtao Yang; Hang Lin; Yixian Wang; Rihong Cao; Jiangteng Li; Yanlin Zhao. Investigation of the correlation between crack propagation process and the peak strength for the specimen containing a single pre-existing flaw made of rock-like material. Archives of Civil and Mechanical Engineering 2021, 21, 1 -21.
AMA StyleHengtao Yang, Hang Lin, Yixian Wang, Rihong Cao, Jiangteng Li, Yanlin Zhao. Investigation of the correlation between crack propagation process and the peak strength for the specimen containing a single pre-existing flaw made of rock-like material. Archives of Civil and Mechanical Engineering. 2021; 21 (2):1-21.
Chicago/Turabian StyleHengtao Yang; Hang Lin; Yixian Wang; Rihong Cao; Jiangteng Li; Yanlin Zhao. 2021. "Investigation of the correlation between crack propagation process and the peak strength for the specimen containing a single pre-existing flaw made of rock-like material." Archives of Civil and Mechanical Engineering 21, no. 2: 1-21.
From the perspective of the mechanical mechanism of slope failure, cohesion c usually plays a different role with friction φ in sliding resistance, which indicates the distinct weights of their reduction factors Fsc and Fsφ to the overall safety factor of slope Fs in the double strength reduction method (DSRM). This study primarily introduced the equivalent influence angle of slope θe, for which c and φ share identical contributions to the safety factor, and investigated its influencing factors, which turns out that θe shows an increasing trend with an increase of slope weight H or slope height γ, but the increasing rate is decreasing. Subsequently, an equivalent influence angle chart was plotted as an effective and advantageous approach to locate the specific value of θe for a given slope. On this basis, the shortest reduction path method was utilized to calculate Fsc and Fsφ, and the stability contributions of c and φ were quantified by the different weight coefficients of Fsc and Fsφ to Fs. The specific weight coefficient could be solved by the correlation between slope angle θ and corresponding θe, thereby developing a new definition of Fs. Ultimately, a modified double strength reduction method was achieved, which was compared with other DSRMs and verified by existing slope examples.
Yifan Chen; Hang Lin; Rihong Cao; Chunyang Zhang. Slope Stability Analysis Considering Different Contributions of Shear Strength Parameters. International Journal of Geomechanics 2021, 21, 04020265 .
AMA StyleYifan Chen, Hang Lin, Rihong Cao, Chunyang Zhang. Slope Stability Analysis Considering Different Contributions of Shear Strength Parameters. International Journal of Geomechanics. 2021; 21 (3):04020265.
Chicago/Turabian StyleYifan Chen; Hang Lin; Rihong Cao; Chunyang Zhang. 2021. "Slope Stability Analysis Considering Different Contributions of Shear Strength Parameters." International Journal of Geomechanics 21, no. 3: 04020265.
From the perspective of macroscopic scale, the majority of natural rock mass should be categorized as non-penetrating jointed rock mass. The existing researches in the field of scale effect of joint properties were mainly implemented on penetrating joints, which contradicts engineering practice, and is of high possibility to make the strength estimation of large natural jointed rock mass inaccurate, leading to serious loss of life and property. In response to such case, a series of numerical calculations of direct shear test on non-penetrating horizontal rock-like joints with different scales were carried out by PFC in this paper, to investigate the scale effect of shear mechanical properties of non-penetrating horizontal rock-like joints. First, the model microparameters were calibrated by three physical experiments to guarantee the precise reproduction of the mechanical performances of target rock and joint. Next, the particle parameters (average particle size dave and radius ratio μ) of model were changed, the effect of particle size on joint strength was studied by direct shear calculation, and the determining method for the values of dave and μ was suggested. Then, based on two distribution forms of non-penetrating horizontal rock-like joint (type I and type II joints), the numerical shear tests were conducted on jointed rock models with different persistence rations and model scales, and the variations of shear stress displacement curve and strength characteristics were analyzed. The results indicate: The lower the persistence ration λ of the joint, the more obvious the negative scale effect of joint shear strength. Besides, the scale effect of shear strength gradually decreases when λ > 0.5 for type I joints while λ > 0.8 for type II joints and the scale effects of joint strength parameters only emerge in the case of λ < 0.2.
Yifan Chen; Hang Lin; Xuran Ding; Shijie Xie. Scale effect of shear mechanical properties of non-penetrating horizontal rock-like joints. Environmental Earth Sciences 2021, 80, 1 -10.
AMA StyleYifan Chen, Hang Lin, Xuran Ding, Shijie Xie. Scale effect of shear mechanical properties of non-penetrating horizontal rock-like joints. Environmental Earth Sciences. 2021; 80 (5):1-10.
Chicago/Turabian StyleYifan Chen; Hang Lin; Xuran Ding; Shijie Xie. 2021. "Scale effect of shear mechanical properties of non-penetrating horizontal rock-like joints." Environmental Earth Sciences 80, no. 5: 1-10.
The damage of the interface between mortar and rock often occurs in engineering projects. The stability of the binary medium joint is the key factor in judging the stability of a hydraulic structure foundation. The shear characteristics of the flat mortar-rock joint were numerically simulated under the direct shear test by finite element using FLAC3D software. The results showed that the internal friction angle of mortar has little influence on the shear strength, its corresponding displacement, strain softening degree and residual shear strength for flat joint. Therefore, considering the roughness of the structural surface, the joint with regular serrated mortar-rock binary medium was established in this paper, and the direct shear test under the condition of constant normal stress was carried out for comparative study. The results showed that the shear strength, residual strength, peak strength displacement and strain softening degree of the serrated structure were strongly correlated with the internal friction angle of mortar. For the regular serrated binary joint, improving the mortar performance can improve the shear performance and stability of the whole structure more effectively than the flat joint. The relationship between the shear strength, residual strength and the friction angle were established respectively.
Wenyu Tang; Hang Lin. Influence of Internal Friction Angle and Interface Roughness on Shear Behavior of Mortar-Rock Binary Medium Joint. Geotechnical and Geological Engineering 2021, 39, 3917 -3929.
AMA StyleWenyu Tang, Hang Lin. Influence of Internal Friction Angle and Interface Roughness on Shear Behavior of Mortar-Rock Binary Medium Joint. Geotechnical and Geological Engineering. 2021; 39 (5):3917-3929.
Chicago/Turabian StyleWenyu Tang; Hang Lin. 2021. "Influence of Internal Friction Angle and Interface Roughness on Shear Behavior of Mortar-Rock Binary Medium Joint." Geotechnical and Geological Engineering 39, no. 5: 3917-3929.
Researches on the energy evolution of the key blocks is helpful to reveal the failure process of locked-segment type slope, whose stability is governed by the locking section along the potential slip surface. In order to study the failure mechanism of the locked segment in the process of slope progressive failure due to strength attenuation, a series of stability analysis on the numerical models of locked-segment type slope were implemented to record the relationship curve between energy and strength reduction coefficient. Then, according to the variation law and characteristic of energy evolution, the failure process of the locked segment was divided into four stages: elastic stage, initial damage stage, extensive damage stage and failure stage. And the reduction coefficient corresponding to the peak of the energy evolution curve was employed to achieve landslide warning. In addition, the method to determine the safety factor of locked-segment type slope was given, and its reliability was verified by comparing with other traditional methods. Finally, the formula for calculating the initial sliding velocity was presented based on the residual strain energy which is defined as the elastic strain energy of the locked segment when the slope is unstable.
Xiangjie Yin; Hang Lin; Yifan Chen; Yi Tang; Yixian Wang; Yanlin Zhao; Weixun Yong. Stability Analysis of Slope Considering the Energy Evolution of Locked Segment. 2021, 1 .
AMA StyleXiangjie Yin, Hang Lin, Yifan Chen, Yi Tang, Yixian Wang, Yanlin Zhao, Weixun Yong. Stability Analysis of Slope Considering the Energy Evolution of Locked Segment. . 2021; ():1.
Chicago/Turabian StyleXiangjie Yin; Hang Lin; Yifan Chen; Yi Tang; Yixian Wang; Yanlin Zhao; Weixun Yong. 2021. "Stability Analysis of Slope Considering the Energy Evolution of Locked Segment." , no. : 1.
Most natural rock masses contain a large number of random joints and fissures, and most of the rock masses at the rock engineering are commonly in both compression and shear stress environment. However, the research on the failure characteristics of complex random jointed rock mass under compressive-shear loading is still limited. To address this gap, this paper uses the particle flow code 2D to establish a discrete fractured rock mass model and carry out a series of numerical tests with different compressive-shear angles (α) and different joint geometric parameters. The effects of compressive-shear angle and joint geometric parameters on the strength and failure characteristics of fractured rock masses are studied. The results indicate that with the increase of α, the peak strength of the specimen decreases gradually, and the failure mode changes from the composite shear failure mode (Mode-I) to a plane shear failure mode (Mode-II) and then to intact shear failure mode (Mode-III). Specifically, the three failure modes occur in the specimens with α = 15°, 30° or 45°, 60°, respectively. The existence of joints affects stress distribution on rock mass during the loading process. Furthermore, the stress at the joint tip is relatively concentrated, while on both sides of the joint is smaller. Three kinds of crack coalescence patterns are observed: tensile, shear, and tensile-shear mixed coalescence. The inclination angle of the rock bridge between adjacent joints affects the specific type of coalescence.
Hang Lin; Biyang Sheng. Failure Characteristics of Complicated Random Jointed Rock Mass Under Compressive-Shear Loading. Geotechnical and Geological Engineering 2021, 39, 3417 -3435.
AMA StyleHang Lin, Biyang Sheng. Failure Characteristics of Complicated Random Jointed Rock Mass Under Compressive-Shear Loading. Geotechnical and Geological Engineering. 2021; 39 (5):3417-3435.
Chicago/Turabian StyleHang Lin; Biyang Sheng. 2021. "Failure Characteristics of Complicated Random Jointed Rock Mass Under Compressive-Shear Loading." Geotechnical and Geological Engineering 39, no. 5: 3417-3435.
Tunnel excavation changes the original stress state which directly leads to the surrounding rock fracture, many researches focus on the stress or displacement evaluation surrounding an opening or a tunnel. Flaws and openings dramatically change the state of internal stress within the rock mass, and the internal stress concentrates at some certain positions surrounding the opening. When the flaws and openings simultaneously exist, the internal stress interacts. To discuss about the stress evolution surrounding the flaw and opening, this study used the PFC program to establish numerical models containing one open flaw and two circular openings. Under uniaxial compression, the stress distributions surrounding the flaw and the openings at different loading stages and different flaw orientations were presented and the principal stress evolutions around the flaw and the openings were analyzed. The proposed numerical method in measuring local stress can be useful to evaluate the local stress distribution and evolution surrounding the flaw and opening.
Xiang Fan; Xudong Jiang; Yixin Liu; Hang Lin; Kaihui Li; Zhongming He. Local stress distribution and evolution surrounding flaw and opening within rock block under uniaxial compression. Theoretical and Applied Fracture Mechanics 2021, 112, 102914 .
AMA StyleXiang Fan, Xudong Jiang, Yixin Liu, Hang Lin, Kaihui Li, Zhongming He. Local stress distribution and evolution surrounding flaw and opening within rock block under uniaxial compression. Theoretical and Applied Fracture Mechanics. 2021; 112 ():102914.
Chicago/Turabian StyleXiang Fan; Xudong Jiang; Yixin Liu; Hang Lin; Kaihui Li; Zhongming He. 2021. "Local stress distribution and evolution surrounding flaw and opening within rock block under uniaxial compression." Theoretical and Applied Fracture Mechanics 112, no. : 102914.
The creep characteristics of joint have an important influence on the long-term stability of rock mass engineering such as tunnels and slopes. In this paper, the sawtooth angle α is taken as the variable, five different numerical models of regular sawtooth joints are established using the discrete element numerical method, to study the shear mechanical characteristics of joints under creep condition. In addition, the shear mechanical properties of joints under transient condition are compared to analysis the influence of creep on the mechanical characteristics of joint. The results show that under shear creep condition: (1) Shear displacement of joint increases stepwise with time. At low sawtooth angles, the difference of joint shear displacement with different normal stresses is large. The long-term shear strength of joint is proportional to normal stress and sawtooth angle. (2) The total absorbed energy U and elastic energy Ue of the joint both increase as the sawtooth angle α increases. Dissipated energy Ud tends to increase first and then decrease with increasing sawtooth angle. Compared with the energy characteristics under transient condition, it is found that the joint under creep condition not only has a lower shear strength, but also requires less total absorbed energy and dissipative energy, and fewer cracks at critical failure. (3) Before the peak strength, the damage variable D increases nonlinearly with the shear displacement. Compared with the transient condition, the damage amount corresponding to the peak strength under the creep condition is smaller, and the evolution rate of the damage variable D with shear displacement at the critical failure is higher.
Xing Zhang; Hang Lin; Yixian Wang; Rui Yong; Yanlin Zhao; Shigui Du. Damage evolution characteristics of saw-tooth joint under shear creep condition. International Journal of Damage Mechanics 2020, 30, 453 -480.
AMA StyleXing Zhang, Hang Lin, Yixian Wang, Rui Yong, Yanlin Zhao, Shigui Du. Damage evolution characteristics of saw-tooth joint under shear creep condition. International Journal of Damage Mechanics. 2020; 30 (3):453-480.
Chicago/Turabian StyleXing Zhang; Hang Lin; Yixian Wang; Rui Yong; Yanlin Zhao; Shigui Du. 2020. "Damage evolution characteristics of saw-tooth joint under shear creep condition." International Journal of Damage Mechanics 30, no. 3: 453-480.
To understand crack coalescence patterns and local strain behaviors near flaw tip for flawed rock subjected to biaxial compression, a series of biaxial compression tests with a lateral stress of 2.0 MPa were carried out on rock-like specimens containing two flaws. The paper classified crack coalescence patterns, measured the local strain concentration near the flaw tip, and analyzed the stress–strain behavior related to crack initiation, propagation, and coalescence. Some interesting cracking behaviors of flawed specimens subjected to biaxial compression were observed. Seven basic crack types (wing crack, anti-wing crack, oblique and coplanar shear cracks, lateral crack, remote crack, and en echelon cracks) are identified and ten patterns of crack coalescences are observed subjected to biaxial compression. In general, the crack coalescence varies from the shear crack coalescence (S-mode) to the tensile wing crack coalescence (T-mode), and then to mixed shear/tensile crack coalescence (TS-mode), with the increase of the rock bridge ligament angle β, ranging from 25 to 120° subjected to biaxial compression. Crack initiation and coalescence usually can be reflected by a load stress rapid drop, a measured strain jump, or turning near flaw tip subjected to biaxial compression. The measured tensile or compression strains near flaw tip tend to increase almost simultaneously with higher axial stress before crack initiation; however, become very complex after crack initiation, due to the stress relaxation and adjustment near flaw tip induced by the combination of crack development and constant lateral stress. The existence of lateral stress results in many fragments in a shear failure mode with local surface spallings in flawed specimens containing two flaws.
Yanlin Zhao; Jian Liao; Yixian Wang; Qiang Liu; Hang Lin; Le Chang. Crack coalescence patterns and local strain behaviors near flaw tip for rock-like material containing two flaws subjected to biaxial compression. Arabian Journal of Geosciences 2020, 13, 1 -18.
AMA StyleYanlin Zhao, Jian Liao, Yixian Wang, Qiang Liu, Hang Lin, Le Chang. Crack coalescence patterns and local strain behaviors near flaw tip for rock-like material containing two flaws subjected to biaxial compression. Arabian Journal of Geosciences. 2020; 13 (23):1-18.
Chicago/Turabian StyleYanlin Zhao; Jian Liao; Yixian Wang; Qiang Liu; Hang Lin; Le Chang. 2020. "Crack coalescence patterns and local strain behaviors near flaw tip for rock-like material containing two flaws subjected to biaxial compression." Arabian Journal of Geosciences 13, no. 23: 1-18.
This paper investigated shear-related roughness classification based on Fuzzy comprehensive evaluation, and established a new strength model of natural rock joint. The joint profiles were extracted from 3D data to evaluate roughness, and a series of direct shear tests were carried out on three kinds of natural rock joints. The height statistical parameters Sm, Sq, Ss and Sk, and the textural statistical parameters Si, Sc, and Z2 were measured by Talysurf morphology instrument. Considering the existence of strong positive relations between Sm and Sq, and Z2 and Si, the four morphological parameters of Si, Sq, Sc, and Sk are considered as the main influencing factors related with rock joint shear behaviors. A new fracture roughness coefficient FRC is proposed based on fuzzy comprehensive evaluation (FCE), which considers that the influence of multi morphology parameters on the roughness of rock joint surface, and generally, the FRC is higher than the JRC. Compared with the previously published shear strength models, the proposed FRC-JCS shear strength model, which can more comprehensively reflect the influence of joint surface morphology parameters to shear strength, are in better agreement with the experimental data.
Yanlin Zhao; Chunshun Zhang; Yixian Wang; Hang Lin. Shear-related roughness classification and strength model of natural rock joint based on fuzzy comprehensive evaluation. International Journal of Rock Mechanics and Mining Sciences 2020, 137, 104550 .
AMA StyleYanlin Zhao, Chunshun Zhang, Yixian Wang, Hang Lin. Shear-related roughness classification and strength model of natural rock joint based on fuzzy comprehensive evaluation. International Journal of Rock Mechanics and Mining Sciences. 2020; 137 ():104550.
Chicago/Turabian StyleYanlin Zhao; Chunshun Zhang; Yixian Wang; Hang Lin. 2020. "Shear-related roughness classification and strength model of natural rock joint based on fuzzy comprehensive evaluation." International Journal of Rock Mechanics and Mining Sciences 137, no. : 104550.
Bolt is popular in the reinforcement of geotechnical engineering, which can significantly improve the strength and stability of jointed rock mass. For bolted joint, the bolting area is a certain scope instead of the entire joint surface; therefore, it is necessary to study the effect of bolt influencing area on the shear strength of rock joints. In this paper, a series of laboratory direct shear tests were executed on the bolted joints to explore the influence of bolts on the joint shear strength, as well as the influencing area of bolt. Via successively changing bolting angle and bolt number, the shear stress-shear displacement curves of bolted joints were recorded and the variation law of shear strength was analyzed. Based on the assumption of the circular influencing area of bolt, the influence coefficient m (defined as the diameter ratio of the influencing area to the bolt) was introduced to establish the theoretical calculation model of the shear strength of bolted joint, which was verified by test results. Furthermore, the value of m was changed, and the shear strengths of bolted joints under different bolting condition were calculated to compare with the test results. The average relative error Eave was selected to determine the optimal value of m under the corresponding bolting condition, and it tends to sufficiently small values under the case of m > 30 for one-bolted joint and m > 25 for two-bolted joint, as well as m > 20 for three-bolted joint, which demonstrates that m can be applied to effectively calculate the actual influencing area of bolt.
Hang Lin; Penghui Sun; Yifan Chen. Shear Strength of Flat Joint considering Influencing Area of Bolts. Advances in Civil Engineering 2020, 2020, 1 -12.
AMA StyleHang Lin, Penghui Sun, Yifan Chen. Shear Strength of Flat Joint considering Influencing Area of Bolts. Advances in Civil Engineering. 2020; 2020 ():1-12.
Chicago/Turabian StyleHang Lin; Penghui Sun; Yifan Chen. 2020. "Shear Strength of Flat Joint considering Influencing Area of Bolts." Advances in Civil Engineering 2020, no. : 1-12.
The natural rock mass prevailingly exists in the form of a fractured rock mass, and freezing-thawing failure of the fractured rock mass is also frequently encountered during geotechnical projects in cold regions. The previous researches and reports in freezing-thawing field principally focused on intact rocks, while rock joints and fractures were rarely considered, which causes great inconvenience to the safety design and stability assessment of engineering. In response to the special climatic conditions of cold regions, the freezing-thawing damage and degradation mechanism of fractured rock were studied in this paper based on existing laboratory experiments and damage mechanics theory. Primarily, a brief review of the progressive damage process of rock in the conventional triaxial compression experiment was given, as well as the determination methods of four characteristic stresses in the prepeak curve. Then, from the microcosmic perspective, the maximum tensile strain yield criterion was used to reflect the microunit strength which was assumed to statistically satisfy the Weibull distribution, deriving the damage evolution equation of fractured rock under the freezing-thawing cycle and load conditions and quantificationally describing the damage evolution law. Consequently, the statistical empirical constitutive relation of fractured rock considering freezing-thawing and loading damages was established. Ultimately, by combining the existing conventional triaxial compression experimental data of freezing-thawing single fractured rocks with the determination methods of characteristic stresses, the relevant constitutive parameters were solved, and the theoretical constitutive relation curves of the fractured rock after freezing-thawing cycles were obtained, which were compared with the experimental results to verify the validity of the established empirical constitutive relation. The study findings can provide a theoretical basis for revealing the freezing-thawing failure mechanism of the fractured rock mass to some extent.
Yifan Chen; Hang Lin; Yixian Wang; Yanlin Zhao. Damage Statistical Empirical Model for Fractured Rock under Freezing-Thawing Cycle and Loading. Geofluids 2020, 2020, 1 -12.
AMA StyleYifan Chen, Hang Lin, Yixian Wang, Yanlin Zhao. Damage Statistical Empirical Model for Fractured Rock under Freezing-Thawing Cycle and Loading. Geofluids. 2020; 2020 ():1-12.
Chicago/Turabian StyleYifan Chen; Hang Lin; Yixian Wang; Yanlin Zhao. 2020. "Damage Statistical Empirical Model for Fractured Rock under Freezing-Thawing Cycle and Loading." Geofluids 2020, no. : 1-12.