The SPOT image analysis in Muzaffarabad Azad Kashmir,northwest Himalayas,Pakistan reveals that the Kashmir earthquake 2005 triggered a number of coseismic mass movements along the hanging wall block of the Muzaffaraba...The SPOT image analysis in Muzaffarabad Azad Kashmir,northwest Himalayas,Pakistan reveals that the Kashmir earthquake 2005 triggered a number of coseismic mass movements along the hanging wall block of the Muzaffarabad Fault.The Neelidandi and Langarpura rock falls have been identified as two major reactivated mass movements with an estimated volume of 3.1 × 106m3and 5.76 × 106m3,respectively.The Neelidandi and Langarpura mass movements were initiated during earthquake in the direction of northwest-southeast extension and northeastsouthwest directed thrusting,respectively.The Neelidandi rock fall occurred in sheared cherty dolomites and limestones of the Cambrian Muzaffarabad Formation,whereas the Langarpura rock fall occurred in alternating clays,shales,claystones,siltstones and sandstones of the Miocene Murree Formation.These rock units along the fault are highly fractured and jointed.The geotechnical maps and geological longitudinal profiles show the relationship between the geometrical characteristics and mechanism of these mass movements.Their characteristics were analyzed according to the role of topographic,seismic,geological and tectonic factors.The steep topography,sheared rocks,lithology,coseismic uplift and strong ground shaking of the hanging wall block along Muzaffarabad Fault facilitated the gravity collapse of these mass movements.展开更多
The downslope movement of detached rock blocks along steep slopes is an important process endangering the safety of infrastructure along the foot of a slope and on the valley bottom,but only limited knowledge is avail...The downslope movement of detached rock blocks along steep slopes is an important process endangering the safety of infrastructure along the foot of a slope and on the valley bottom,but only limited knowledge is available on the influence of various factors on the velocity and distance of movement of such blocks.We discuss the influence of the mass and shape of the rock blocks,the steepness of the slope,and the thickness of the overburden on the slope,on the distance of movement of rock blocks which was observed in 256 field experiments with differently shaped blocks from 3 different positions on the slope with a height of 176 m.The statistical evaluation of the results of the field tests shows that the slope condition of gradient and overburden is the main factor,the form of rock masses is the second factor,and the mass is the third of the influencing factors.It is the maximum average acceleration for movement of rock masses when the mass of rock masses is 15≤m27 kg,the form of rock masses is flake,the condition of gradient is on average 59.6° and the overburden is basic exposed bedrock and a small quantity of gravel-soil in the experiment condition.It is the minimum average acceleration for movement of rock masses when the mass of rock masses is 9.5≤m15 kg,the form of rock masses is rectangular,the condition of gradient is on average 39° and the overburden is gravel-soil and cinder.Then,the foundation for impact energy is provided and the new feasible methods to prevent potential unstable rock masses are put forward.展开更多
以阿勒泰市骆驼峰景区崩塌灾害为工程背景,采用地质分析法研究其形成机制,利用赤平极射投影与数值计算得出典型崩塌危岩体的稳定性,通过现场调查与Rocfall模拟软件分析崩塌落石的运动特征,并提出防治方案。研究结果表明:成岩过程中形成...以阿勒泰市骆驼峰景区崩塌灾害为工程背景,采用地质分析法研究其形成机制,利用赤平极射投影与数值计算得出典型崩塌危岩体的稳定性,通过现场调查与Rocfall模拟软件分析崩塌落石的运动特征,并提出防治方案。研究结果表明:成岩过程中形成的结构面在后期持续的地质应力的作用下张开甚至贯通,以及强烈的冻融循环作用是形成骆驼峰崩塌的主要原因;数值计算结果显示,崩塌体在外界扰动因素(降雨/融雪、地震)的作用下稳定系数降低明显,多数处于欠稳定-不稳定状态;崩塌落石形成后经历抛掷、碰撞、弹跳、滚动等运动状态,弹跳高度最大值为11.3 m,总动能最大值为304.6 k J。根据分析成果,提出"主动+被动"相结合的崩塌防治措施,既避免破坏景观,又达到了治理效果。展开更多
基金the University of Azad Jammu and Kashmir Muzaffarabad,for funding the research under Faculty Development Programme
文摘The SPOT image analysis in Muzaffarabad Azad Kashmir,northwest Himalayas,Pakistan reveals that the Kashmir earthquake 2005 triggered a number of coseismic mass movements along the hanging wall block of the Muzaffarabad Fault.The Neelidandi and Langarpura rock falls have been identified as two major reactivated mass movements with an estimated volume of 3.1 × 106m3and 5.76 × 106m3,respectively.The Neelidandi and Langarpura mass movements were initiated during earthquake in the direction of northwest-southeast extension and northeastsouthwest directed thrusting,respectively.The Neelidandi rock fall occurred in sheared cherty dolomites and limestones of the Cambrian Muzaffarabad Formation,whereas the Langarpura rock fall occurred in alternating clays,shales,claystones,siltstones and sandstones of the Miocene Murree Formation.These rock units along the fault are highly fractured and jointed.The geotechnical maps and geological longitudinal profiles show the relationship between the geometrical characteristics and mechanism of these mass movements.Their characteristics were analyzed according to the role of topographic,seismic,geological and tectonic factors.The steep topography,sheared rocks,lithology,coseismic uplift and strong ground shaking of the hanging wall block along Muzaffarabad Fault facilitated the gravity collapse of these mass movements.
基金supported by the National Natural Science Foundation of China (No. 50539050)
文摘The downslope movement of detached rock blocks along steep slopes is an important process endangering the safety of infrastructure along the foot of a slope and on the valley bottom,but only limited knowledge is available on the influence of various factors on the velocity and distance of movement of such blocks.We discuss the influence of the mass and shape of the rock blocks,the steepness of the slope,and the thickness of the overburden on the slope,on the distance of movement of rock blocks which was observed in 256 field experiments with differently shaped blocks from 3 different positions on the slope with a height of 176 m.The statistical evaluation of the results of the field tests shows that the slope condition of gradient and overburden is the main factor,the form of rock masses is the second factor,and the mass is the third of the influencing factors.It is the maximum average acceleration for movement of rock masses when the mass of rock masses is 15≤m27 kg,the form of rock masses is flake,the condition of gradient is on average 59.6° and the overburden is basic exposed bedrock and a small quantity of gravel-soil in the experiment condition.It is the minimum average acceleration for movement of rock masses when the mass of rock masses is 9.5≤m15 kg,the form of rock masses is rectangular,the condition of gradient is on average 39° and the overburden is gravel-soil and cinder.Then,the foundation for impact energy is provided and the new feasible methods to prevent potential unstable rock masses are put forward.
文摘以阿勒泰市骆驼峰景区崩塌灾害为工程背景,采用地质分析法研究其形成机制,利用赤平极射投影与数值计算得出典型崩塌危岩体的稳定性,通过现场调查与Rocfall模拟软件分析崩塌落石的运动特征,并提出防治方案。研究结果表明:成岩过程中形成的结构面在后期持续的地质应力的作用下张开甚至贯通,以及强烈的冻融循环作用是形成骆驼峰崩塌的主要原因;数值计算结果显示,崩塌体在外界扰动因素(降雨/融雪、地震)的作用下稳定系数降低明显,多数处于欠稳定-不稳定状态;崩塌落石形成后经历抛掷、碰撞、弹跳、滚动等运动状态,弹跳高度最大值为11.3 m,总动能最大值为304.6 k J。根据分析成果,提出"主动+被动"相结合的崩塌防治措施,既避免破坏景观,又达到了治理效果。
