The catastrophic rockslide,which frequently triggers numerous severe disasters worldwide,has drawn much attention globally;however,understanding the initiation mechanism of catastrophic rockslides in the absence of ty...The catastrophic rockslide,which frequently triggers numerous severe disasters worldwide,has drawn much attention globally;however,understanding the initiation mechanism of catastrophic rockslides in the absence of typical single triggering factors related to strong seismic activity or torrential precipitation continues to be challenging within the global scientific community.This study aims to determine the mechanism of the three largest catastrophic rockslides in the eastern Tibetan Plateau,Yigong,Xinmo,and Baige,over the past 20 years using field investigation,remote sensing,and runoff analysis.Instead of the conventional driving factors of heavy rainfall and strong earthquakes,the multi-wing butterfly effects(MWBE)of climatic factors and weak earthquakes are for the first time identified as drivers of the catastrophic rockslide disasters.First,strong tectonic uplift,fast fluvial incision,high-density faults,and large regional water confluence formed the slopes in the critical regime,creating the source conditions of rockslide.Second,the MWBE of early dry-heat events and antecedent rainfall,combined with imminent weak earthquakes,initiated rockslide.Third,the delayed amplified runoff moving toward the sliding surface and lowering the strength of the locking-rock segment constituted the fundamental mechanism of the MWBE on rockslide.The catastrophic rockslide was ultimately inferred to be a nonlinear chaotic process;however,prediction and forecasting of rockslide based on the MWBE in the early stages are possible and essential.This finding presents a new perspective concerning forecasting progressive landslides.展开更多
To reveal the damage characteristics and catastrophic failure mechanism of coal rock caused by gas adsorption,physical tests and theoretical methods are employed.The results show that adsorption swelling can damage co...To reveal the damage characteristics and catastrophic failure mechanism of coal rock caused by gas adsorption,physical tests and theoretical methods are employed.The results show that adsorption swelling can damage coal rock,which can be distinguished by fractal dimension.A fitting relationship between the adsorption damage and fractal dimension is proposed by experimental testing and theoretical analysis.High gas adsorption pressure proves to be the dominant factor that leads to coal failure softening and gas outburst disasters.Three main parameters concerning adsorption damage include the change rate of released energy density,the transition difference in the post-peak acoustic emission(AE)b value and the change rate of cumulative AE energy.Results show that all the three parameters present a step-type decreasing change with the increase in fractal dimension,and the fractal dimension shows a linear relationship within the same failure mode.Finally,a method is proposed to evaluate coal rock disaster transformation,based on the aforementioned three main parameters of adsorption damage.展开更多
Scuffing, a major cause of failure in automobile engines, is considered as a dynamicprocess in this study. Local adhesions may occur randomly in lubricated contacts due to the exis-tence of asperity contact and breakd...Scuffing, a major cause of failure in automobile engines, is considered as a dynamicprocess in this study. Local adhesions may occur randomly in lubricated contacts due to the exis-tence of asperity contact and breakdown of lubricating films. Scuffing would take place if the localevents develop rapidly into a large-scale plastic deformation and catastrophic failure. A systemdynamic established in the present paper allows one to predict dynamic behavior of a tribologicalsystem through numerical solutions of a group of differential equations. A simplified analysis basedon this model confirms that the system will develop into a state of instability if the friction force atthe interface increases with temperature.展开更多
The frequency of large dam failures all over the world, with a high toll of lives lost, pinpoints the still unsolved problems of flood risk resulting from the presence of large dams in built-up areas. Some of these fa...The frequency of large dam failures all over the world, with a high toll of lives lost, pinpoints the still unsolved problems of flood risk resulting from the presence of large dams in built-up areas. Some of these failures and other related incidents took place in Italy in the past century. The purpose of this paper is to discuss the three worst cases of dam failures occurring in Italy, analyzing the causes which led to collapse. They are the dams of Gleno （1923）, Molare （1935） and Stava （1985）.展开更多
1 研究背景幂律奇异性是材料灾变破坏及地震发生时的一个典型前兆特征(Voight,1989;Xue et al,2018)。在灾变破坏发生时,系统的响应函数R=du/dU发散到无穷大,表现出临界幂律奇异性(Xue et al,2018)。其中,u是系统响应量,U是系统的加载...1 研究背景幂律奇异性是材料灾变破坏及地震发生时的一个典型前兆特征(Voight,1989;Xue et al,2018)。在灾变破坏发生时,系统的响应函数R=du/dU发散到无穷大,表现出临界幂律奇异性(Xue et al,2018)。其中,u是系统响应量,U是系统的加载控制量。响应函数R的临界幂律奇异性是灾变破坏能量准则的体现,对大理岩、花岗岩试样进行的准静态单轴压缩实验表明,响应函数幂律奇异性指数分布在-1/2到-1之间。展开更多
Meteoroid and orbital debris(M/OD) may cause severe damages or even catastrophic failures for long-term manned spacecrafts in orbit due to the hypervelocity impact(HVI) destruction.It is essential to quantitatively as...Meteoroid and orbital debris(M/OD) may cause severe damages or even catastrophic failures for long-term manned spacecrafts in orbit due to the hypervelocity impact(HVI) destruction.It is essential to quantitatively assess the M/OD risk of manned spacecraft.In this paper,the catastrophic failure as-sessment function is successfully integrated into the Meteoroid & Orbital Debris Assessment and Op-timization System Tools(MODAOST),which is the M/OD risk assessment system developed by China Academy of Space Technology.The survivability assessment for the US Lab by MODAOST was con-sistent with that of the Manned Spacecraft Crew Survivability computer code(MSCSurv).Meanwhile,the simulation process showed that this function was more effective than MSCSurv for the application of the standard methodology of M/OD risk assessment instead of the Monte Carlo model.This function expands the ability of MODAOST in predicting the survivability of the typical catastrophic failure modes such as crew hypoxia and the critical cracking.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.U20A20110)the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0906)+2 种基金the Key R&D Projects of Tibet Autonomous Region Science and Technology Pro ject(Grant No.XZ202101ZD0013G)the International Cooperation Overseas Platform Project,CAS(Grant No.131C11KYSB20200033)the Outstanding Talent Project of Thousand Talents Program in China.
文摘The catastrophic rockslide,which frequently triggers numerous severe disasters worldwide,has drawn much attention globally;however,understanding the initiation mechanism of catastrophic rockslides in the absence of typical single triggering factors related to strong seismic activity or torrential precipitation continues to be challenging within the global scientific community.This study aims to determine the mechanism of the three largest catastrophic rockslides in the eastern Tibetan Plateau,Yigong,Xinmo,and Baige,over the past 20 years using field investigation,remote sensing,and runoff analysis.Instead of the conventional driving factors of heavy rainfall and strong earthquakes,the multi-wing butterfly effects(MWBE)of climatic factors and weak earthquakes are for the first time identified as drivers of the catastrophic rockslide disasters.First,strong tectonic uplift,fast fluvial incision,high-density faults,and large regional water confluence formed the slopes in the critical regime,creating the source conditions of rockslide.Second,the MWBE of early dry-heat events and antecedent rainfall,combined with imminent weak earthquakes,initiated rockslide.Third,the delayed amplified runoff moving toward the sliding surface and lowering the strength of the locking-rock segment constituted the fundamental mechanism of the MWBE on rockslide.The catastrophic rockslide was ultimately inferred to be a nonlinear chaotic process;however,prediction and forecasting of rockslide based on the MWBE in the early stages are possible and essential.This finding presents a new perspective concerning forecasting progressive landslides.
基金financial support by the National Natural Science Foundation of China(Grant Nos.51974186,51774164 and 51774048)。
文摘To reveal the damage characteristics and catastrophic failure mechanism of coal rock caused by gas adsorption,physical tests and theoretical methods are employed.The results show that adsorption swelling can damage coal rock,which can be distinguished by fractal dimension.A fitting relationship between the adsorption damage and fractal dimension is proposed by experimental testing and theoretical analysis.High gas adsorption pressure proves to be the dominant factor that leads to coal failure softening and gas outburst disasters.Three main parameters concerning adsorption damage include the change rate of released energy density,the transition difference in the post-peak acoustic emission(AE)b value and the change rate of cumulative AE energy.Results show that all the three parameters present a step-type decreasing change with the increase in fractal dimension,and the fractal dimension shows a linear relationship within the same failure mode.Finally,a method is proposed to evaluate coal rock disaster transformation,based on the aforementioned three main parameters of adsorption damage.
文摘Scuffing, a major cause of failure in automobile engines, is considered as a dynamicprocess in this study. Local adhesions may occur randomly in lubricated contacts due to the exis-tence of asperity contact and breakdown of lubricating films. Scuffing would take place if the localevents develop rapidly into a large-scale plastic deformation and catastrophic failure. A systemdynamic established in the present paper allows one to predict dynamic behavior of a tribologicalsystem through numerical solutions of a group of differential equations. A simplified analysis basedon this model confirms that the system will develop into a state of instability if the friction force atthe interface increases with temperature.
文摘The frequency of large dam failures all over the world, with a high toll of lives lost, pinpoints the still unsolved problems of flood risk resulting from the presence of large dams in built-up areas. Some of these failures and other related incidents took place in Italy in the past century. The purpose of this paper is to discuss the three worst cases of dam failures occurring in Italy, analyzing the causes which led to collapse. They are the dams of Gleno （1923）, Molare （1935） and Stava （1985）.
文摘1 研究背景幂律奇异性是材料灾变破坏及地震发生时的一个典型前兆特征(Voight,1989;Xue et al,2018)。在灾变破坏发生时,系统的响应函数R=du/dU发散到无穷大,表现出临界幂律奇异性(Xue et al,2018)。其中,u是系统响应量,U是系统的加载控制量。响应函数R的临界幂律奇异性是灾变破坏能量准则的体现,对大理岩、花岗岩试样进行的准静态单轴压缩实验表明,响应函数幂律奇异性指数分布在-1/2到-1之间。
文摘Meteoroid and orbital debris(M/OD) may cause severe damages or even catastrophic failures for long-term manned spacecrafts in orbit due to the hypervelocity impact(HVI) destruction.It is essential to quantitatively assess the M/OD risk of manned spacecraft.In this paper,the catastrophic failure as-sessment function is successfully integrated into the Meteoroid & Orbital Debris Assessment and Op-timization System Tools(MODAOST),which is the M/OD risk assessment system developed by China Academy of Space Technology.The survivability assessment for the US Lab by MODAOST was con-sistent with that of the Manned Spacecraft Crew Survivability computer code(MSCSurv).Meanwhile,the simulation process showed that this function was more effective than MSCSurv for the application of the standard methodology of M/OD risk assessment instead of the Monte Carlo model.This function expands the ability of MODAOST in predicting the survivability of the typical catastrophic failure modes such as crew hypoxia and the critical cracking.
