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A Comparative Study of Supervised Classification Methods for Investigating Landslide Evolution in the Mianyuan River Basin,China

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Journal of Earth Science 2023年第2期34卷 316-329页

作者： Yujie Long Weile Li runqiu huang Qiang Xu Bin Yu Gang Liu State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China Sichuan Metallurgical Geological Survey and Design Group Co. LtdChengdu 610081China College of Earth Sciences Chengdu University of TechnologyChengdu 610059China

The Ms8.0 Wenchuan earthquake of 2008 dramatically changed the terrain surface and caused long-term increases in the scale and frequency of landslides and debris *** changing trend of landslides in the earthquake-affected area over the decade since the earthquake remains largely *** this study,we were able to address this issue using supervised classification methods and multitemporal remote sensing images to study landslide evolution in the worst-affected area(Mianyuan River Basin)over a period of ten *** images were processed using the maximum likelihood method and random forest algorithm to automatically map landslide occurrence from 2007 to *** principal findings are as follows:(1)when compared with visual image analysis,the random forest algorithm had a good average accuracy rate of 87%for landslide identification;(2)postevent landslide occurrence has generally decreased with time,but heavy monsoonal seasons have caused temporary spikes in activity;and(3)the postearthquake landslide activity in the Mianyuan River Basin can be divided into a strong activity period(2008 to 2011),medium activity period(2012 to 2016),and weak activity period(post 2017).Landslide activity remains above the prequake level,with damaging events being rare but continuing to ***-term remote sensing and on-site monitoring are required to understand the evolution of landslide activity after strong earthquakes.

关键词： Wenchuan earthquake Mianyuan River Basin automatic detection evolutionary trend maximum likelihood method random forest algorithm engineering geology

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Development and distribution of geohazards triggered by the 5.12 Wenchuan Earthquake in China

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Science China(Technological Sciences) 2009年第4期52卷 810-819页

作者： huang runqiu LI WeiLe State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China

As the Wenchuan Earthquake was of high magnitude and shallow seismic focus, it caused great dam- age and serious geohazards. By the field investigation and the interpretation of remote-sensing infor- mation after the earthquake and by using means of GIS technology, the distribution of geohazards triggered by the earthquake are analyzed and the conclusions are as follows: (1) The earthquake geo- hazards showed the feature of zonal distribution along the earthquake fault zone and linear distribution along the rivers; (2) the distribution of earthquake geohazards had a marked hanging wall effect, for the development density of geohazards in the hanging wall of earthquake fault zone was obviously higher than that in the foot wall and the width of strong development zone in the hanging wall was about 10 km; (3) the topographical slope was a main factor which controlled the development of earthquake geo- hazards and a vast majority of hazards were distributed on the slopes of 20° to 50°; (4) the earthquake geohazards had a corresponding relationship with the elevation and micro-landform, for most hazards happened in the river valleys and canyon sections below the elevation of 1500 to 2000 m, particularly in the upper segment of canyon sections (namely, the turning point from the dale to the canyon). Thin ridge, isolated or full-face space mountains were most sensitive to the seismic wave, and had a striking amplifying effect. In these areas, collapses and landslides were most likely to develop; (5) the study also showed that different lithologies determined the types of geohazards, and usually, landslides oc- curred in soft rocks, while collapses occurred in hard rocks.

关键词： 5.12 Wenchuan Earthquake seismogenic geohazard distribution remote-sensing information hanging wall effect GIS analysis

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Determination of T-stress using finite element analysis

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Science China(Technological Sciences) 2017年第8期60卷 1211-1220页

作者： TANG ShiBin DONG Zuo huang runqiu State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology

A method that uses finite element analysis to determine the non-singular stress(T-stress) at a crack tip is proposed in this study.T-stress includes two components:the T_x-stress parallel to the tangent of the crack at its tip and the 7Vstress perpendicular to this *** effects of contact and friction on both the T_x-and T_y-stresses on the crack flanks are considered in the *** the method uses a single standard elastic finite element analysis derived directly from the equation of the stress fields around the crack tip and does not require any assumptions or simplification,it can be used to determine the T-stress for any given geometry and loading *** results are used to calibrate the results,which exhibited good agreement and to discuss the T-stress computational ***,the T_x-and T_y-stresses in center-cracked Brazilian disc(CCBD) specimens subjected to diametrical or partially distributed compression were numerically computed,and the effects of contact and friction on the T_x-and T_y-stresses are discussed.

关键词：有限元分析应力测定裂纹尖端应力计算方法组成部分载荷条件数值计算巴西圆盘

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Geo-engineering Lessons Learned from the 2008 Wenchuan Earthquake in Sichuan and Their Significance to Reconstruction

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Journal of Mountain Science 2011年第2期8卷 176-189页

作者： huang runqiu State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology Chengdu 610059 Sichuan China

The 2008 Wenchuan earthquake in Sichuan of China was the result of quake-triggering along an active several hundred-kilometer-long fault. The subsequent landslides and debris flow geohazards are dominating factors in planning post-disaster recovery and rebuilding. This paper presents recommendations for coping with large-scale geohazards and disasters. It is essential to establish a national emergency management system for huge scale catastrophe and earthquake precursor identification. Town construction must be kept away from active faults, especially to improve town safety in areas with high risk of seismic and geological hazards, and it is important to improve geohazard investigation and remediation for mountain areas that have become loosened by earthquake activity. Geological factors must be better understood to reduce direct and secondary risks and effects of earthquakes. Site selections for public relocation require clear and informed analysis of geological and social risk reduction, so that relocation, infrastructure reconstruction, and commemorative relic-sites can be protected.

关键词：地震触发地质工程汶川县四川省地质灾害调查风险分析活动断层城市建设

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生态环境部部长黄润秋在全国两会“部长通道”答记者问

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中国环保产业 2023年第3期 11-13页

作者：光明日报记者黄润秋不详生态环境部

3月5日上午,在十四届全国人大一次会议开幕会结束后,2023年全国两会首场“部长通道”在人民大会堂开启。生态环境部部长黄润秋走上“部长通道”,并回答媒体记者提问。光明日报记者:党的二十大报告提出,中国式现代化是人与自然和谐共生... 详细信息

3月5日上午,在十四届全国人大一次会议开幕会结束后,2023年全国两会首场“部长通道”在人民大会堂开启。生态环境部部长黄润秋走上“部长通道”,并回答媒体记者提问。光明日报记者:党的二十大报告提出,中国式现代化是人与自然和谐共生的现代化。请问,您如何理解人与自然和谐共生的现代化?生态环境部在推进人与自然和谐共生的现代化方面将重点开展哪些工作?

关键词：生态环境黄润秋中国式现代化开幕会全国两会答记者问

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Sedimentary Characteristics of the Pleistocene Outwash Accumulation and their Implications for Paleoclimate Change in the Midstream of Dadu River,Southwestern China

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Acta Geologica Sinica(English Edition) 2012年第4期86卷 924-931页

作者： TU Guoxiang huang runqiu DENG Hui LI Yanrong State Key Laboratory of Geo-hazard Prevention and Geo-environment Protection Chengdu University of Technology The University of Mississippi MS 38677USA

Ancient outwash accumulations, deposited in Pleistocene with complicated sedimentary characteristics, are discovered in the midstream valley of Dadu River, Southwestern China. Their sedimentation characteristics are investigated for gaining a deep insight into the dependency of Paleoclimate changes in this area. This is achieved by means of detailed site investigation, sampling and laboratory tests （grain size distribution and Electron Spin Resonance dating tests） for two representative outwash accumulations. Based on the present study, several main conclusions are drown out as follows： 1） The accumulations are composed mainly of coarse soils （coarse fraction is over 50%） and very coarse soils （coarse fraction is about 20%-35%, and very coarse fraction is over 55%）; 2） The coarse soils are sub-rounded well-sorted and sub-stratified to well-stratified, while the very coarse soils exhibit sub-rounded to sub-angular and poorly-sorted; 3） The accumulations are postulated to have been intermittently deposited in three time periods. This is evidenced by two layers of weathered/ residual clay, purple to brick red in color; and 4） It is inferred that the temperature in the study area increased over three time periods, i.e., 280 ka B.P. to 120 ka B.P., 110 ka B.P. to 80 ka B.P. and 70 ka B. P. to 25 ka B.P., and declined twice at 120 ka B.P. and 77 ka B.P. respectively.

关键词： outwash accumulations sedimentary properties paleoclimate changes

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Mechanism and Geo-mechanics Models of Landslides Triggered by 5.12 Wenchuan Earthquake

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Journal of Mountain Science 2011年第2期8卷 200-210页

作者： huang runqiu XU Qiang HUO Junjie State Key Laboratory of Geohazards Prevention and Geoenvironment Protection Chengdu University of Technology Chengdu Sichuan China

Due to the extremely high magnitude, long duration, and the complicated geo-environment in the disaster area, the great 5.12 Wenchuan Earthquake not only produced a huge number of landslides and rockfalls, but also involved complicated dynamic processes. These processes are quite different from the characteristics of landslides and rockfalls under general gravitational force, and presently human knowledge is very poor in this field. In order to describe the special dynamic processes, some terms such as shattering-cracking, shattering-sliding, shattering-falls and ejection are defined in this paper. Combined with slope structures, a mechanism classification system of strong earthquake-triggered landslide and rockfall is suggested, which is divided into 5 categories and 14 types. This paper also analyzes the basic characteristics, dynamic processes and geo-mechanics conceptual models of some typologies, especial the type of shattering-sliding for most large-scales landsides. This paper initially reveals the formation mechanism, geo-mechanics models and dynamic features of landslides and rockfalls triggered by the great Wenchuan Earthquake.

关键词：地质力学模型山体滑坡地震触发汶川机制持续时间地理环境术语定义

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Long-term Hardening Characteristics of Prestressed Anchorage Grout

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Journal of Mountain Science 2012年第6期9卷 752-759页

作者： WANG Sheng CHEN Liyi huang runqiu JIANG Zhaoqun WANG Yanshu State Key Laboratory of Geohazard Prevention&Geoenvionment Protection Chengdu University of TechnologyChengdu 610059China The Insititute of Exploration Technology of CAGS Chengdu 611734China

Grout plays an important role in the transmission and maintenance of anchoring force,and in the protection of anchorage materials against ***,the hardening characteristics of grout directly affect the anchoring effectivity and long-term *** have excavated a prestressed anchorage which has been in service for 20 years,and have tested the grout which has worked for that long period under complicated geological conditions through strength tests and have analyzed its mineral composition using scanning electron microscopy(SEM) and X-ray diffraction(XRD).The results show that the mineral composition of the 12.5 m segment differs from other segments,and corresponds with poor coagulation characteristics of the 12.5 m segment *** shows that unhydrated tricalcium silicate may be the reason for the localized poor coagulation.

关键词：预应力锚固灌浆强化特性扫描电子显微镜复杂地质条件 X-射线衍射强度测试凝固特性

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Pn-wave velocity and anisotropy of the western Sichuan and Longmen Mountain region,China

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Science China Earth Sciences 2010年第11期53卷 1665-1670页

作者： Xu Yi Li ZhiWei huang runqiu Liu JianHua Liu JinSong Chinese Acad Sci Inst Geol & Geophys Key Lab Petr Resources Res Beijing 100029 Peoples R China Chengdu Univ Technol State Key Lab Geohazard Prevent & Geoenvironm Chengdu 610059 Peoples R China

Pn-wave velocity and anisotropy beneath the western Sichuan and adjacent region are inverted by a tomography method using arrival data from earthquakes recorded by the Sichuan Earthquake Network. It is followed by an analysis of the uppermost mantle structure of the Longmen Mountain region and the deep tectonics of the Ms8.0 earthquake in Wenchuan. Our results reveal a prominent velocity contrast across the Longmenshan fault: low velocities in the Songpan-Ganzi mountain range and high velocities in the Sichuan basin. They indicate that the Songpan-Ganzi mountain range is underlain by a weak uppermost mantle, which is easy to create ductile flow, whereas the Sichuan basin has a mechanically strong uppermost mantle. These features reflect a difference of the lithospheric mantle beneath tectonically active mountain range and stable basin. The boundary between the high and low velocities is coincident with the Longmenshan fault. Bordered by Wenchuan, the northern part of the boundary is parallel to the fault belt and aftershock distribution, but the southern part of the boundary deviates from the fault belt and is bent toward the Sichuan basin. The Ms8.0 earthquake in Wenchuan is located at the flexural part between them, where a strong heterogeneity is shown in the velocity variation across and parallel to the boundary. This area is reasonably believed as a potential location for regional stress accumulation and release in the Longmen Mountain region, reflecting a prominent character in the deep structure around Wenchuan. Pn-wave anisotropy reveals the mantle flow that is consistent with the eastward movement of the Tibetan Plateau. This process provided deep dynamic sourse for tectonic deformation in the Longmen Mountain region and for the occurrence of the Wenchuan Ms8.0 earthquake, but it is clearly affected by the strong lithosphere of the Sichuan basin. There is no correlation between the Pn-wave anisotropy and the Longmenshan fault, hence, this fault system is on

关键词： western Sichuan Longmen Mountain Pn velocity anisotropy Wenchuan earthquake

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A Simple Lumped Mass Model to Describe Velocity of Granular Flows in a Large Flume

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Journal of Mountain Science 2012年第2期9卷 221-231页

作者： YANG Qingqing CAI Fei UGAI Keizo SU Zhiman huang runqiu XU Qiang Department of Civil and Environmental Engineering Gunma University Kiryu 3768515 Japan Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China State Key Laboratory of Geo-Hazard Prevention and Geo-Environment Protection Chengdu University of Technology Chengdu 610059 China

This paper presents a lumped mass model to describe the run-out and velocity of a series of large flume tests,which was carried out to investigate some propagation mechanisms involved in rapid,dry,dense granular flows and energy transformation when the flows encountered obstacles and reoriented their movement *** between predicted and measured results show that the trend of predicted velocities was basically matched with that of measured *** scrutiny of test videos reveals that subsequent particles with a higher velocity collided with slowed fronts to make them accelerate. However,this simple model cannot reflect collisions between particles because it treated released materials as a rigid ***,the predicted velocity was somewhat lower than the measured velocity in most *** the flow changed its direction due to the variation in slope inclination,the model predicted a decrease in *** predicted decrease in velocity was less than the measured one within a reasonable range of 10% or *** some cases in which a convexity was introduced,the model also predicted the same trend of velocities as measured in the *** velocity increased greatly after the materials took a ballistic trajectory from the vertex of the convexity,and reduced dramatically when they finally made contact with the base of the lower *** difference between prediced and measured decrease in velocity was estimated to be about 5% due to the ***,the simple lumped mass model based on the energy approach could roughly predict the run-out and velocity of granular flows,although it neglected internal deformation,intergranular collision and friction.

关键词：集中质量模型颗粒流动速度比大型渡槽模型预测测试测量能量方法水槽试验

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