With the increasing excavation depth of underground engineering,engineering problems such as large deformation and rock burst caused by high geo-stress brings new challenges to the excavation and reinforcement of surr...With the increasing excavation depth of underground engineering,engineering problems such as large deformation and rock burst caused by high geo-stress brings new challenges to the excavation and reinforcement of surrounding rock in deep underground engineering.The traditional rock bolt is prone to brittle fracture under high geo-stress due to its low elongation.Therefore,this work aims to develop a novel energy-absorbing bolt with constant resistance and large displacement to reinforce the surrounding rock with a risk of large deformation or rockburst.The novel energy-absorbing bolt refereed as rolling extrusion rock bolt(RE bolt)is mainly consists of sleeve tube with a variable cross-section,energy absorption slider with steel balls embedded,steel bar connected with the energy absorption slider.The rolling extrusion is adopted to produce the resistance force of the RE bolt,which avoids the sudden attenuation of resistance force and the abrasion of the energy absorption slider.The static pull test is conducted to study the resistance force and deformation characteristics of the RE bolt with different specifications.Results imply that the RE bolt has higher resistance force,larger deformation capacity and energy absorption capacity.The work of this study provides an effective solution for the reinforcement of surrounding rock in deep rock engineering.展开更多
The Gaoloushan Tunnel in Longnan City,Gansu Province,China,frequently experiences rockburst disasters due to high in-situ stress.Managing rockburst in deep-buried tunnels remains a challenging issue.This paper employs...The Gaoloushan Tunnel in Longnan City,Gansu Province,China,frequently experiences rockburst disasters due to high in-situ stress.Managing rockburst in deep-buried tunnels remains a challenging issue.This paper employs RFPA(Rock Failure Process Analysis)software to establish a calculation model of constant resistance and large deformation(CRLD)anchorages and analyzes the effects of different support methods and pre-stress levels on rockburst.We simulate the process of tunnel rockburst disasters and find that ordinary anchor support incurs rockburst on the right arch waist and arch top,forming a V-shaped explosion pit.CRLD anchor support has several advantages in rockburst control,such as more uniform stress distribution in the surrounding rock,a uniform distribution of plastic zones,less noticeable damage to the tunnel,and effective control of the arch top displacement.The effectiveness of the CRLD anchor support under varying pre-stress conditions shows that a higher prestress results in a smaller plastic zone of the surrounding rock and arch top displacement and a lower number of acoustic emission signals,which better explains the excavation compensation effect.Moreover,adding long anchorages in the deep surrounding rock area can better control rockburst and reduce surrounding rock deformation.Based on these findings,we propose a comprehensive control system that combines long and short anchorages and provides the optimal scheme based on calculations.Therefore,by using high-prestress CRLD anchor support and the combination of long and short anchorages at critical positions,we can enhance the integrity of the surrounding rock,effectively absorb the energy released by the surrounding rock deformation,and reduce the incidence of rockburst disasters.展开更多
Based on the new large de formation theory of Stokes-Chen Strain-Rotation Decomposition Theorem and study on shear-tensile deformation of bolts (Chen Zhida, 1979), a new method of determining bolt’s large de formatio...Based on the new large de formation theory of Stokes-Chen Strain-Rotation Decomposition Theorem and study on shear-tensile deformation of bolts (Chen Zhida, 1979), a new method of determining bolt’s large de formation based on the measurement or displacement has been prerented. Theoretical formulas of global resistance on bolted joints under shear-tensile load have also been proposed. The validity of the theory has ben conflrmed by experimental results iu lab.展开更多
This paper attempts to present the findings involving rockbursts classification, rockburst failure criteria, and related control measures. Experimental investigations were performed using the strainburst testing machi...This paper attempts to present the findings involving rockbursts classification, rockburst failure criteria, and related control measures. Experimental investigations were performed using the strainburst testing machine and impact-induced rockburst testing machine. According to the stress paths and experimental methods, rockbursts were classified into two major groups, i.e. the strainbursts and impact-induced bursts. The mechanisms and criteria of rockburst obtained from experimental investigations were discussed. Then, the developments of constant-resistance and large-deformation bolt （CRLDB）, which can adapt itself to the external loading at a constant resistance by elongating continually, were introduced. The deformation energy Of country rocks with large deformation can be absorbed by CRLDBs. Finally, the principles and the experimental results for control and prevention of rockburst using the CRLDBs were presented.展开更多
Rock bolting technique is an important reinforcement measure in the geotechnical engineering practice.New rock bolts have been continuously emerging through the development of rock supporting technology.Complex condit...Rock bolting technique is an important reinforcement measure in the geotechnical engineering practice.New rock bolts have been continuously emerging through the development of rock supporting technology.Complex conditions,such as high crustal stress,extremely soft rock,and strong mining disturbance often occur in the deep mining,resulting in large deformation of the surrounding rock masses.Since the deformation of traditional rock bolts is generally below 200 mm,failure often occurs to the rock bolts because of insufficient deformability.To effectively control the large deformation of surrounding rock masses caused by complex conditions,it is necessary to develop large deformation rock bolts with high constant resistance,also called energy-absorbing bolts.This paper systematically reviews the development of large deformation rock bolts and the structure,energy absorption mechanism,anchorage performance,and mechanical properties of several typical large deformation rock bolts.The advantages and disadvantages of existing large deformation rock bolts are compared and the concept of constant resistance large deformation support is introduced.展开更多
在抵抗岩体冲击、剪切和能量吸收等诸多方面,具有负泊松比效应的材料比传统意义下的泊松比材料表现出更为优异的性能。因此,针对普通锚索无法抵抗矿山滑坡大变形灾害而发生锚索拉断等问题,研发了具有负泊松比效应的恒阻大变形监测锚索,...在抵抗岩体冲击、剪切和能量吸收等诸多方面,具有负泊松比效应的材料比传统意义下的泊松比材料表现出更为优异的性能。因此,针对普通锚索无法抵抗矿山滑坡大变形灾害而发生锚索拉断等问题,研发了具有负泊松比效应的恒阻大变形监测锚索,该缆索集监测-预警-控制功能于一体,具有高恒阻、大变形、超强吸能等特性,已经成功应用于矿山滑坡灾害监控领域。通过现场静力拉拔试验,对3种不同规格恒阻大变形缆索的轴向变形、径向变形和恒阻力进行连续测量,试验结果证明3种不同规格的恒阻大变形监测缆索均具有恒阻吸能特性,当恒阻值分别达到200、500和850 k N时,最大变形量可达2 000 mm,填补了国内外大变形缆索的研究空白。展开更多
基金the support of the Natural Science Foundation of Hubei Province(2023AFB589)Natural Science Foundation of Chongqing(Grant No.2023NSCQ-LZX0070).
文摘With the increasing excavation depth of underground engineering,engineering problems such as large deformation and rock burst caused by high geo-stress brings new challenges to the excavation and reinforcement of surrounding rock in deep underground engineering.The traditional rock bolt is prone to brittle fracture under high geo-stress due to its low elongation.Therefore,this work aims to develop a novel energy-absorbing bolt with constant resistance and large displacement to reinforce the surrounding rock with a risk of large deformation or rockburst.The novel energy-absorbing bolt refereed as rolling extrusion rock bolt(RE bolt)is mainly consists of sleeve tube with a variable cross-section,energy absorption slider with steel balls embedded,steel bar connected with the energy absorption slider.The rolling extrusion is adopted to produce the resistance force of the RE bolt,which avoids the sudden attenuation of resistance force and the abrasion of the energy absorption slider.The static pull test is conducted to study the resistance force and deformation characteristics of the RE bolt with different specifications.Results imply that the RE bolt has higher resistance force,larger deformation capacity and energy absorption capacity.The work of this study provides an effective solution for the reinforcement of surrounding rock in deep rock engineering.
基金funded by the National Natural Science Foundation of China(52174096,42277174)the Fundamental Research Funds for the Central Universities(2022YJSSB03)the Scientific and Technological Projects of Henan Province(232102320238)。
文摘The Gaoloushan Tunnel in Longnan City,Gansu Province,China,frequently experiences rockburst disasters due to high in-situ stress.Managing rockburst in deep-buried tunnels remains a challenging issue.This paper employs RFPA(Rock Failure Process Analysis)software to establish a calculation model of constant resistance and large deformation(CRLD)anchorages and analyzes the effects of different support methods and pre-stress levels on rockburst.We simulate the process of tunnel rockburst disasters and find that ordinary anchor support incurs rockburst on the right arch waist and arch top,forming a V-shaped explosion pit.CRLD anchor support has several advantages in rockburst control,such as more uniform stress distribution in the surrounding rock,a uniform distribution of plastic zones,less noticeable damage to the tunnel,and effective control of the arch top displacement.The effectiveness of the CRLD anchor support under varying pre-stress conditions shows that a higher prestress results in a smaller plastic zone of the surrounding rock and arch top displacement and a lower number of acoustic emission signals,which better explains the excavation compensation effect.Moreover,adding long anchorages in the deep surrounding rock area can better control rockburst and reduce surrounding rock deformation.Based on these findings,we propose a comprehensive control system that combines long and short anchorages and provides the optimal scheme based on calculations.Therefore,by using high-prestress CRLD anchor support and the combination of long and short anchorages at critical positions,we can enhance the integrity of the surrounding rock,effectively absorb the energy released by the surrounding rock deformation,and reduce the incidence of rockburst disasters.
文摘Based on the new large de formation theory of Stokes-Chen Strain-Rotation Decomposition Theorem and study on shear-tensile deformation of bolts (Chen Zhida, 1979), a new method of determining bolt’s large de formation based on the measurement or displacement has been prerented. Theoretical formulas of global resistance on bolted joints under shear-tensile load have also been proposed. The validity of the theory has ben conflrmed by experimental results iu lab.
文摘This paper attempts to present the findings involving rockbursts classification, rockburst failure criteria, and related control measures. Experimental investigations were performed using the strainburst testing machine and impact-induced rockburst testing machine. According to the stress paths and experimental methods, rockbursts were classified into two major groups, i.e. the strainbursts and impact-induced bursts. The mechanisms and criteria of rockburst obtained from experimental investigations were discussed. Then, the developments of constant-resistance and large-deformation bolt （CRLDB）, which can adapt itself to the external loading at a constant resistance by elongating continually, were introduced. The deformation energy Of country rocks with large deformation can be absorbed by CRLDBs. Finally, the principles and the experimental results for control and prevention of rockburst using the CRLDBs were presented.
基金financial supports from the Key Special Project of National Natural Science Foundation of China(No.41941018)Open Research Fund of Technology Innovation Center for Geological Environment Monitoring,China(No.2020KFK1212001).
文摘Rock bolting technique is an important reinforcement measure in the geotechnical engineering practice.New rock bolts have been continuously emerging through the development of rock supporting technology.Complex conditions,such as high crustal stress,extremely soft rock,and strong mining disturbance often occur in the deep mining,resulting in large deformation of the surrounding rock masses.Since the deformation of traditional rock bolts is generally below 200 mm,failure often occurs to the rock bolts because of insufficient deformability.To effectively control the large deformation of surrounding rock masses caused by complex conditions,it is necessary to develop large deformation rock bolts with high constant resistance,also called energy-absorbing bolts.This paper systematically reviews the development of large deformation rock bolts and the structure,energy absorption mechanism,anchorage performance,and mechanical properties of several typical large deformation rock bolts.The advantages and disadvantages of existing large deformation rock bolts are compared and the concept of constant resistance large deformation support is introduced.
文摘在抵抗岩体冲击、剪切和能量吸收等诸多方面,具有负泊松比效应的材料比传统意义下的泊松比材料表现出更为优异的性能。因此,针对普通锚索无法抵抗矿山滑坡大变形灾害而发生锚索拉断等问题,研发了具有负泊松比效应的恒阻大变形监测锚索,该缆索集监测-预警-控制功能于一体,具有高恒阻、大变形、超强吸能等特性,已经成功应用于矿山滑坡灾害监控领域。通过现场静力拉拔试验,对3种不同规格恒阻大变形缆索的轴向变形、径向变形和恒阻力进行连续测量,试验结果证明3种不同规格的恒阻大变形监测缆索均具有恒阻吸能特性,当恒阻值分别达到200、500和850 k N时,最大变形量可达2 000 mm,填补了国内外大变形缆索的研究空白。
