Research on Shield Tunnelling Parameters Correlation in Composite Strata by Ziqi Guo, Huipeng Zhang, Xiaoyang Shi, Zhi Huang, Yiyong Xu, Zhiqiang Zhang

“…The complex formation has complicated geological changes, including soft rock, hard rock, and soft and hard inhomogeneous formation. …”
Get full text

Experimental Study of Gangue Layer Weakening with Deep-Hole Presplitting Blasting by Jianchi Hao, Lifeng Ren, Hu Wen, Duo Zhang

“…This is particularly so at thin coal seams, where a large number of hard rock layers known as gangue are often present, which seriously affect the normal operation of the shearer and reduce coal output. …”
Get full text

Defining Stress Thresholds of Granite Failure Process Based on Acoustic Emission Activity Parameters by Xingdong Zhao, Lei Deng, Jitao Xu

“…In order to study the crack closure stress threshold σcc of hard rock, crack initiation stress threshold σci, stress threshold σcs of crack interaction, and damage stress threshold σc d, uniaxial compression test was carried out on granite samples. …”
Get full text

Particle Flow Analysis of Mechanical Properties and Failure Behaviour in Composite Rock Strata with Holes by Chuanwei Zang, Hongmo Zhu, Miao Chen, Shuo Yang, Liu Yang, Jia Zhou, Zuoru Zhang, Yang Chen

“…It shows that the first area to be damaged in composite rock strata transfers from soft rock to hard rock with the increase in dip angle. With the increase in confining pressure, the range of tensile stress concentration area decreases substantially, while the range of compressive stress concentration area changes less.…”
Get full text

Calculation Method for the Critical Thickness of a Karst Cave Roof at the Bottom of a Socketed Pile by Nie Qingke, Li Xilai, Yuan Wei, Wang Anli, Wang Wei, Jia Xiangxin, Shang Weidong

“…The analysis results show that less load at the bottom of the pile, higher quality of rock mass, and more hard rock all lead to a smaller critical thickness-diameter ratio, whereas the critical thickness-to-diameter ratio is greater. …”
Get full text

Study on Characteristics of Mining Earthquake in Multicoal Seam Mining under Thick and Hard Strata in High Position by Shuli Wang, Guangli Zhu, Kaizhi Zhang, Lei Yang

“…Using SOS microseismic monitoring system to collect microseismic events and date during multicoal seam mining, characteristic and difference of microseismic in multicoal seam mining under thick and hard rock in high position is analyzed systematically. …”
Get full text

An Electro Breakdown Damage Model for Granite and Simulation of Deep Drilling by High-Voltage Electropulse Boring by Changping Li, Longchen Duan, Songcheng Tan, Victor Chikhotkin, Xiaohui Wang

“…Electropulse rock breaking has wide application prospects in hard rock drilling and ore breaking. At present, there are no suitable physical mathematical models that describe electropulse boring (EPB) processes under confining pressures. …”
Get full text

Formation Mechanism and Stability Analysis of the Hejia Landslide by Hao Zhang, Zaiqiang Hu, Xingzhou Chen, Hongru Li

“…Through field investigation and analysis of regional geological conditions, it is concluded that Hejia landslide is a large-scale landslide, through long-term sliding-bending deformation; it is generated from the external hard rock with thick layers and sliding zone for layered soft rock; the formation mechanism of landslide is as follows: (1) high-steep and hard-soft layered slope is the slope structure condition that caused the large landslide; (2) the existence of thick soft rock belt provides material conditions for the formation of slip surface; (3) certain air conditions provide displacement space for the separation and disintegration of the sliding body, and the landslide is stable at present. …”
Get full text

Influence of Support Stiffness on Dynamic Characteristics of the Hydraulic Pipe Subjected to Basic Vibration by Wei Qu, Huailiang Zhang, Wei Li, Wenqian Sun, Lina Zhao, Haihui Ning

“…The basic vibration generated during the tunneling process of hard rock tunnel results in the change of the support stiffness of the hydraulic pipe, which causes the problem of reduction of pipe transmission efficiency. …”
Get full text

Experimental Study on Mechanical Properties of Deep Buried Granite under Different Confining Pressures by Jun Zhao, Tan Zhang

“…Brittle failure of hard rock poses a serious threat to the stability of surrounding rock in deep underground engineering. …”
Get full text

Numerical Simulation of Conical Pick Cutting Arc Rock Plate Fracture Based on ANSYS/LS-DYNA by Zhiwen Wang, Qingliang Zeng, Zhenguo Lu, Lirong Wan, Xin Zhang, Guanshun Gao

“…The new method of rock breaking based on the combination of circular sawblade and conical pick was proposed to improve the effectiveness of hard rock breaking. The numerical simulation method was applied to research the conical pick cutting arc rock plate by ANSYS/LS-DYNA. …”
Get full text

Determination of Shape Coefficient in Elastic Modulus Estimation with Penetration Test by Tongbin Zhao, Rui Mao, Kai Fang, Biwen Zhang, Fenghai Yu

“…The shape coefficient of hard rock is higher than that of soft rock. Shape coefficient should be selected reasonably according to the penetration depth in practical application, and the reason, furthermore, why back-calculated shape coefficient deviates from the theoretical value is also discussed.…”
Get full text

Research on Cutting Characteristics of Rock Plate with Two Sides Fixed and Two Sides Free by Zhenguo Lu, Qingliang Zeng, Zhihai Liu, Guanshun Gao, Peisi Zhong

“…Conical pick wear is an urgent problem in the roadway excavation caused by hard rock difficult to break. The traditional method of increasing cutting power to improve cutting performance of conical pick significantly increases pick wear. …”
Get full text

Study on Dynamic Constitutive Model of Weakly Consolidated Soft Rock in Western China by Lei Wang, Hongming Su, Yue Qin, Shiguan Chen

“…It was also found that the constitutive equation was applicable to express the dynamic mechanical properties of rock-like materials such as hard rock, soft rock, frozen soil, raw coal, and concrete. …”
Get full text

Simulation and Analysis of a Split Drill Bit for Pneumatic DTH Hammer Percussive Rotary Drilling by Yuanling Shi, Conghui Li

“…Reverse circulation impact drilling has the advantages of high drilling efficiency and less dust, which can effectively form holes in hard rock and gravel layer. As integral reverse circulation drill bits used in the conventional down-the-hole (DTH) hammers are only suitable for specific formations, the whole set of DTH hammer needs to be replaced when drilling different formations. …”
Get full text

Assessment of Surface Runoff for Tank Watershed in Tamil Nadu Using Hydrologic Modeling by Marykutty Abraham, Riya Ann Mathew

“…The study area is Urapakkam watershed with a chain of 3 tanks having an aerial extent of 4.576 km2 with hard rock formation underneath and thus has limited scope for groundwater recharge. …”
Get full text

Application of Presplitting Blasting Technology in Surrounding Rock Control of Gob-Side Entry Retaining with Hard Roof: A Case Study by Shuang Gong, Yi Tan, Yunpeng Liu, Dan Zhu, Yang Yu

“…The comprehensive control measures for the surrounding rock of 7135 roadway with roof cutting and pressure relief and gob retaining are formulated, including safety assurance technical measures, such as advanced precrack and seam cutting, roof reinforcement and support, gangue retaining protection beside the roadway, lagging temporary support, and on-site industrial test monitoring scheme. Aiming at the hard rock roof, the “deep hole + shallow hole” presplitting blasting roof cutting technology is developed, and the economic and reasonable blasting parameters are determined. …”
Get full text

Experimental Evaluation of Multiple Frost Heaving Parameters for Preflawed Granite in Beizhan Iron Mining, Xinjiang, China by Yu Wang, Dayu Long, Zulifeiya Rejuti, Huajian Wang

“…The sensitivity analysis reveals the influential order of the considered factors to peak FHF, which is the rock lithology, flaw width, flaw cement type, and flaw length. For low-porosity hard rock, increasing flaw width, flaw length, and flaw cement strength can improve the probability of frost heaving failure. …”
Get full text

Numerical Investigation of the Influence of Roof Fracturing Angle on the Stability of Gob-Side Entry Subjected to Dynamic Loading by Zhibiao Guo, Lei Zhang, Zhibo Ma, Feixiang Zhong, Jingchao Yu, Siming Wang

“…Furthermore, dynamic loading was applied to research the influence of fracture of hard rock strata on the entry stability. The global model was validated with the field data. …”
Get full text

Study of SCA-Induced Rock Crack Propagation under Different Stress Conditions Using a Modified Cohesive Element Method by Shen Wang, Hani Mitri, Huamin Li, Dongyin Li, Wen Wang

“…When inducing cracks, soundless cracking agents (SCAs) do not generate vibration, harmful gas, dust, nor flying rock fragment, making them suitable for hard rock roof breaking, rock burst prevention, oil or gas reservoir stimulation, and building demolition. …”
Get full text