For a soft rock tunnel under high stress in jointed and swell soft rock （HJS）, two construction schemes pilot-tunneling enlarging excavation and step-by-step excavation were optimized using FLAC20, and the deformati...For a soft rock tunnel under high stress in jointed and swell soft rock （HJS）, two construction schemes pilot-tunneling enlarging excavation and step-by-step excavation were optimized using FLAC20, and the deformation effects of the two construction schemes were verified by field tests. Based on engineer- ing geological investigation and mechanical analysis of large deformations, the complex deformation mechanisms of stress expansion and structural deformation of the soft rock tunnel were confirmed, and support countermeasures from the complex deformation mechanism converted to a single type were proposed, and the support parameters were optimized by field tests. These technologies were proved by engineering practice, which produced significant technical and economic benefits.展开更多
Comparing with the resin bolt, the hydraulic expansion bolt has different anchoring mechanism and application advantage. According to the working mechanism of the hydraulic expansion bolt, its anchoring force is expre...Comparing with the resin bolt, the hydraulic expansion bolt has different anchoring mechanism and application advantage. According to the working mechanism of the hydraulic expansion bolt, its anchoring force is expressed in four forms including support anchoring force, tension anchoring force, expansion anchoring force and tangent anchoring force, and their values can be obtained on the basis of each calculation formula. Among them, the expansion anchoring force, which is the unique anchoring force of the hydraulic expansion bolt, can provide confining pressure to increase the strength of rock. Aiming at solving the problem of stability control in the soft rock roadway in Jinbaotun Coal Mine which has a double layer of 40 U-type sheds and cannot provide enough resistance support to control floor heave, the study reveals the mechanism of floor heave in the soft rock roadway, and designs the reasonable support parameters of the hydraulic expansion bolts. The observed results of floor convergence indicate that the hydraulic expansion bolts can prevent the development and flow of the plastic zone in the floor rock to control floor heave. Research results enrich the control technology in the soft rock roadway.展开更多
Geomechanics in deep mines becomes more complex and structural support in soft rock can be very difficult.Highly stressed soft rock subject to expansion deformation is particularly difficult to control.The Tiefa Coal ...Geomechanics in deep mines becomes more complex and structural support in soft rock can be very difficult.Highly stressed soft rock subject to expansion deformation is particularly difficult to control.The Tiefa Coal Industry Group Daqiang Coal Mine is used as an example.A ventilation shaft,à550 horsehead,is located in tertiary soft rock.Analysis of the reasons for deformation shows an intumescent rock,which is easily damaged.Field observations and theoretical analysis led to a design capable of stabilizing the rock.A combination of spray,anchors,anchor bolts,and soft corner coupled truss supports allowed the deformation to be controlled.This provides a model for similar designs when support of a horsehead roadway is required.展开更多
A rationally designed support for deep roadways excavated in broken soft rock under high stress was investigated. The deformation and failure characteristics and the mechanism of ''yielding support'' w...A rationally designed support for deep roadways excavated in broken soft rock under high stress was investigated. The deformation and failure characteristics and the mechanism of ''yielding support'' was studied for anchor bolts and cables. The rail roadway of the 2-501 working face in the Liyazhuang Mine of the Huozhou coal area located in Shanxi province was used for field trials. The geological conditions used there were used during the design phase. The new ''highly resistant, yielding'' support system has a core of high strength, yielding bolts and anchor cables. The field tests show that this support system adapts well to the deformation and pressure in the deep broken soft rock. The support system effectively controls damage to the roadway and ensures the long term stability of the wall rock and safe production in the coal mine. This provides a remarkable economic and social benefit and has broad prospects for fur- ther application.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 51474188, 51074140 and 51310105020)the Natural Science Foundation of Hebei Province (No. E2014203012)the Program for Taihang Scholars
文摘For a soft rock tunnel under high stress in jointed and swell soft rock （HJS）, two construction schemes pilot-tunneling enlarging excavation and step-by-step excavation were optimized using FLAC20, and the deformation effects of the two construction schemes were verified by field tests. Based on engineer- ing geological investigation and mechanical analysis of large deformations, the complex deformation mechanisms of stress expansion and structural deformation of the soft rock tunnel were confirmed, and support countermeasures from the complex deformation mechanism converted to a single type were proposed, and the support parameters were optimized by field tests. These technologies were proved by engineering practice, which produced significant technical and economic benefits.
基金support by the National Natural Science Foundation of China (No.51174195)the Fundamental Research Funds for the Central Universities of China (No.2010QNA31)
文摘Comparing with the resin bolt, the hydraulic expansion bolt has different anchoring mechanism and application advantage. According to the working mechanism of the hydraulic expansion bolt, its anchoring force is expressed in four forms including support anchoring force, tension anchoring force, expansion anchoring force and tangent anchoring force, and their values can be obtained on the basis of each calculation formula. Among them, the expansion anchoring force, which is the unique anchoring force of the hydraulic expansion bolt, can provide confining pressure to increase the strength of rock. Aiming at solving the problem of stability control in the soft rock roadway in Jinbaotun Coal Mine which has a double layer of 40 U-type sheds and cannot provide enough resistance support to control floor heave, the study reveals the mechanism of floor heave in the soft rock roadway, and designs the reasonable support parameters of the hydraulic expansion bolts. The observed results of floor convergence indicate that the hydraulic expansion bolts can prevent the development and flow of the plastic zone in the floor rock to control floor heave. Research results enrich the control technology in the soft rock roadway.
基金supported by the National Basic Research Program of China (No.2006CB202200)the Ministry of Education Innovation Team Project (No. IRT0656)+2 种基金the Central University Basic Research Special Fund Operating Expense (No.2009QL06)the New Century Excellent Talents Support Projects of Ministry of Education (No.NCET-08-0833)the National Natural Science Foundation of China (No.41040027)
文摘Geomechanics in deep mines becomes more complex and structural support in soft rock can be very difficult.Highly stressed soft rock subject to expansion deformation is particularly difficult to control.The Tiefa Coal Industry Group Daqiang Coal Mine is used as an example.A ventilation shaft,à550 horsehead,is located in tertiary soft rock.Analysis of the reasons for deformation shows an intumescent rock,which is easily damaged.Field observations and theoretical analysis led to a design capable of stabilizing the rock.A combination of spray,anchors,anchor bolts,and soft corner coupled truss supports allowed the deformation to be controlled.This provides a model for similar designs when support of a horsehead roadway is required.
基金supported by the National Natural Science Foundation of China (No. 50874103)the National Basic Research Program of China (No. 2010CB226805)+1 种基金the Natural Science Foundation of Jiangsu Province (No. BK2008135)as well as by the Open Foundation of State Key Laboratory of Geomechanics and Deep Underground Engineering (No. SKLGDUEK0905)
文摘A rationally designed support for deep roadways excavated in broken soft rock under high stress was investigated. The deformation and failure characteristics and the mechanism of ''yielding support'' was studied for anchor bolts and cables. The rail roadway of the 2-501 working face in the Liyazhuang Mine of the Huozhou coal area located in Shanxi province was used for field trials. The geological conditions used there were used during the design phase. The new ''highly resistant, yielding'' support system has a core of high strength, yielding bolts and anchor cables. The field tests show that this support system adapts well to the deformation and pressure in the deep broken soft rock. The support system effectively controls damage to the roadway and ensures the long term stability of the wall rock and safe production in the coal mine. This provides a remarkable economic and social benefit and has broad prospects for fur- ther application.
