The creep-slip behavior of creeping landslides is closely related to the creep characteristics of slope rock.This study analyzed the creep behavior of ultra-soft mudstone from the Gaomiao landslide in Haidong City,Qin...The creep-slip behavior of creeping landslides is closely related to the creep characteristics of slope rock.This study analyzed the creep behavior of ultra-soft mudstone from the Gaomiao landslide in Haidong City,Qinghai Province,China.Uniaxial creep tests were carried out on ultra-soft mudstone with various moisture contents.The test results indicated that the creep duration of the rock sample with a natural moisture content of 9%is 2400 times longer than that of the sample with a natural moisture content of 13%,while its accumulated strain is 70%of the latter.For the rock sample with a natural moisture content of 9.80%,the creep duration under 0.5 MPa load is 80%of that under 0.25 MPa load,yet the accumulated strain is 1.4 times greater.Additionally,porosity significantly influences the creep behavior of mudstone.Analysis of the cause of the Gaomiao landslide and field monitoring data indicates that the instability of the Gaomiao landslide is related to the moisture content of the landslip mass and external forces.The creep-slip curves of landslides and the creep deformation curves of rocks share a common trend.Precisely identifying the moment when the shift occurs from steady state creep to accelerated creep is critical for comprehending slope instability and rock failure.Moreover,this study delves deeper into the issue of the consistency between landslide creep and rock deformation.展开更多
Since the 1960 s, mining science and technology in China has experienced two technical innovations, i.e.the ‘‘Masonry Beam Theory(MBT)" and ‘‘Transfer Rock Beam Theory(TRBT)". Based on those theories, th...Since the 1960 s, mining science and technology in China has experienced two technical innovations, i.e.the ‘‘Masonry Beam Theory(MBT)" and ‘‘Transfer Rock Beam Theory(TRBT)". Based on those theories, the conventional mining method(being called the 121 mining method) was established, consisting of excavating two tunnels with a pillar left for mining a working panel. However, with increasing mining depth,engineering geological disasters in the underground caverns have been frequently encountered. In addition, the use of the coal-pillar mining results in a large amount of coal resources unexploited. In order to address the problems above, the ‘‘Roof Cut Short-Arm Beam Theory(RCSBT), being called the 110 mining method)" was proposed by He Manchao in 2008. The 110 mining method features the mining of one coal seam panel, excavating necessarily only one roadway tunnel and leaving no pillars. Realization of the 110 mining method includes the following steps:(1) directional pre-splitting roof cutting,(2) supporting the roof by using high Constant Resistance Large Deformation bolt/cable(CRLD), and(3) blocking gangue by hydraulic props. This paper presents an overview of the principles, techniques and application of the 110 mining method. Special emphasis is placed on the numerical simulation of the geostress distribution found in the mining panel using the 110 method compared to that of the 121 method. In addition, the stress distribution on the ‘‘short beam" left by the roof cutting when performing the 110 method was also investigated using both numerical simulation and theoretical formulation.展开更多
基金The work described in this paper is partially supported by the Second Tibetan Plateau Scientific Expedition and Research Grant(2019QZKK0708)ARC Discovery Project grants(DP210100437,DP230100126),for which the authors are very grateful.
文摘The creep-slip behavior of creeping landslides is closely related to the creep characteristics of slope rock.This study analyzed the creep behavior of ultra-soft mudstone from the Gaomiao landslide in Haidong City,Qinghai Province,China.Uniaxial creep tests were carried out on ultra-soft mudstone with various moisture contents.The test results indicated that the creep duration of the rock sample with a natural moisture content of 9%is 2400 times longer than that of the sample with a natural moisture content of 13%,while its accumulated strain is 70%of the latter.For the rock sample with a natural moisture content of 9.80%,the creep duration under 0.5 MPa load is 80%of that under 0.25 MPa load,yet the accumulated strain is 1.4 times greater.Additionally,porosity significantly influences the creep behavior of mudstone.Analysis of the cause of the Gaomiao landslide and field monitoring data indicates that the instability of the Gaomiao landslide is related to the moisture content of the landslip mass and external forces.The creep-slip curves of landslides and the creep deformation curves of rocks share a common trend.Precisely identifying the moment when the shift occurs from steady state creep to accelerated creep is critical for comprehending slope instability and rock failure.Moreover,this study delves deeper into the issue of the consistency between landslide creep and rock deformation.
文摘Since the 1960 s, mining science and technology in China has experienced two technical innovations, i.e.the ‘‘Masonry Beam Theory(MBT)" and ‘‘Transfer Rock Beam Theory(TRBT)". Based on those theories, the conventional mining method(being called the 121 mining method) was established, consisting of excavating two tunnels with a pillar left for mining a working panel. However, with increasing mining depth,engineering geological disasters in the underground caverns have been frequently encountered. In addition, the use of the coal-pillar mining results in a large amount of coal resources unexploited. In order to address the problems above, the ‘‘Roof Cut Short-Arm Beam Theory(RCSBT), being called the 110 mining method)" was proposed by He Manchao in 2008. The 110 mining method features the mining of one coal seam panel, excavating necessarily only one roadway tunnel and leaving no pillars. Realization of the 110 mining method includes the following steps:(1) directional pre-splitting roof cutting,(2) supporting the roof by using high Constant Resistance Large Deformation bolt/cable(CRLD), and(3) blocking gangue by hydraulic props. This paper presents an overview of the principles, techniques and application of the 110 mining method. Special emphasis is placed on the numerical simulation of the geostress distribution found in the mining panel using the 110 method compared to that of the 121 method. In addition, the stress distribution on the ‘‘short beam" left by the roof cutting when performing the 110 method was also investigated using both numerical simulation and theoretical formulation.
