黄土梁滑坡型泥石流２＃ 沟工程治理及效果评价

目前对谷坊、拦砂坝、排导槽等治理措施研究较多,但对滑坡型泥石流的治理研究较少.２００８年９月２４日,四川省北川县陈家坝乡黄土梁发生特大滑坡,诱发其下游的２＃ 沟发生特大泥石流,导致沟口１０３国道被掩埋,堵塞都坝河.为防止泥石流再次发生,对２
＃ 沟泥石流进行了工程治理及治理效果评价.治理措施采用“２＃ 沟中游４座浅拦坝＋２＃ 支沟中游３座浅拦坝＋下游起点设置总长３４．７m 束流堤,总长１５６．４m 排导槽,终点设置总长２２．１m 导流堤,排导槽与１０３国道相交处,采用桥梁工程跨越排导槽”,中游和下游统筹的治理方案,并分析了各分项治理工程的作用.与２００８年９月２４日暴雨相比,２０１３年８月７日和２０１６年７月２１日２次强降雨活动未发生泥石流灾害,验证了黄土梁２＃ 沟泥石流防治工程效果较好,为类似滑坡型泥石流工程防治提供了参考.      

浅析怀仁县新家园镇小峪沟泥石流治理工程变形监测

对小峪沟泥石流治理工程护堤挡墙和弃渣场挡墙进行平面位移测量、对河道防下切拱坝进行沉降测量,为施工期间及工程竣工后建(构)筑物变形情况提供准确、及时的监测数据,确保建(构)筑工程的安全。     

四川汶川七盘沟“7·11”泥石流破坏建筑物的特征与力学模型

2013年7月11日,四川省汶川县威州镇七盘沟暴发大规模泥石流。通过实地调查和测量,获取了98份建筑物破坏样本。泥石流中大石块、漂木和生活废弃物是参与破坏的主要介质;建筑物长轴方向与流向垂直时,更易遭受破坏;而长轴方向与流向平行且规则分布时,首个遭遇泥石流的建筑物会严重破坏,但也起到阻挡泥石流和耗能的作用,较好地保护了其后的建筑物;当建筑物分布不规则时,首个和凸出的建筑物均遭受冲击破坏;距泥石流出口和主流线越近,建筑物破坏越严重。分析建筑物破坏特征发现:受损建筑物表现的破坏模式因结构类型不同而异;若以梁和柱为承重构件,其破坏主要因柱体受冲后产生塑性铰或被剪断,致建筑物倾斜或倒塌,而以砌体为承重构件者,其破坏表现为承重墙体产生裂缝或垮塌致建筑物整体倒塌。参照建筑物破坏模式,以静力学极限平衡理论为基础,提出建筑物柱体和墙体破坏的临界条件计算公式。最后,依据泥石流的破坏方式和建筑物受损模式,将七盘沟建筑物的破坏划分为5个等级,并讨论了甘肃舟曲泥石流和本次灾害期间建筑物破坏特征的异同。本研究从案例分析的角度,为泥石流危险区城镇及居民点建筑物规划布局和结构设计提供参考。     

泥石流的运动规律分析及其防治建议——以湘南白岭沟泥石流为例

文章以湖南省南部白岭沟泥石流灾害为例,对其运动规律进行了计算分析,提出了有针对性的综合治理措施,对历史上没有观测资料的泥石流灾害的治理具有一定的指导意义.     

紫阳滑坡治理工程实例分析

本文介绍紫阳骨坡治理工程中有关抗滑桩的设计与施工。文中详细地论述了设计中设计人员应根据工程的具体情况去灵活处理的一些技术问题，如确定有关参数的选择原则，计算上的条件简化和一些具体技术细节的处理方法等．     

对采煤区潜在泥石流治理的探讨

受采煤活动影响,采煤区地质灾害比较发育,尤其山区以潜在泥石流更为发育。本文通过对某采煤区地质环境条件调查分析,全面掌握了研究区地质灾害现状,据此分析研究区潜在泥石流的形成条件,对治理潜在泥石流提出一套相对完整的措施。     

四川石棉熊家沟泥石流形成机理与成灾特征分析

四川石棉熊家沟曾于2013年7月4日爆发泥石流,该次泥石流物源类型多样、形成机理复杂,并发生堵塞主河的次生灾害链,具有代表性。通过研究,本次泥石流是在强降雨条件下,以中上游沟道松散物为启动点、沿程下切拉槽、崩滑不断参与运动的一场由自然因素形成的地质灾害。泥石流形成因素分为强降雨、沟道物源启动、崩滑规模扩大3个方面。参与熊家沟泥石流启动汇集的物质来源为沟道物源和崩滑物源,其中,沟道物源量占总量的81.55%。物源补给以沟道松散物为主,崩滑直接提供物源量小分散。经过“7·04”灾害后,流域沟道淤积抬升,形成新的沟道松散物,为下次泥石流埋下了隐患。熊家沟泥石流的成灾模式类型多样,表现为淤积抬高、撞击冲毁、堵塞主河、淹没上游。通过堵河经验公式判别,“7·04”熊家沟泥石流的形成特征极易发生堵河,当地政府与防灾减灾部门应有的放矢做好地质灾害防治工作。      

栾川县石庙镇常门村干江沟泥石流形成机理浅析

干江沟位于栾川县城西部伏牛山北麓的石庙镇常门村,该沟道储存大量松散物质,中上游有尾矿库,尾矿库溃坝引发沟道泥石流,损失惨重。本文从降水条件、洪水流速分析入手,研究沟道颗粒启动形成泥石流的临界速度,从而判断洪水为本次泥石流形成创造了有利条件,尾矿库溃坝是决定条件。尾矿库溃决后,洪水携带矿粉形成巨大洪流以较快的流速拖拽揭起沟床砂石及冲垮沟岸松散堆积物混合形成泥石流。通过泥石流形成机理和溃坝分析,提出预防方案,为地灾减灾提供地质依据。     

牛眠沟流域泥石流形成条件、发展趋势及其防治探讨

汶川地震使牛眠沟流域变成了一个多泥石流灾害的区域,到目前为止,已经发生7次大规模泥石流灾害。经研究,该流域诱发泥石流灾害的3个基本条件非常发育,而目前正处于发展阶段,在震后5~10年内的雨季,极易发生危害性较大、冲击力较强的大规模降雨型泥石流。如果考虑直接利用主沟内沉积的泥石流堆积物,在主沟堆积区的中上游左右两侧修建约为沟宽一半的交替式拦挡土石坝、在中下游修建与沟宽大致相等的拦挡土石坝及在相邻两坝间修建与沟向相对且具有一定坡度斜坡的土木防治工程,可实现消能与耗能双重目的。     

山东省日照市挪庄村崩塌地质灾害治理工程分析

日照市东港区后村镇挪庄村崩塌地质灾害点高差大、坡度陡,危害对象多,自1998—2021年多次发生局部崩塌,造成道路破坏及房屋受损,严重威胁着人民群众的生命财产安全。本文通过现场调查、地质测绘及工程勘察等技术手段,查清了崩塌体失稳机理的主要原因,分析了现状稳定性,通过采用圆弧滑动条分法计算,计算出边坡稳定性系数为0.761,边坡属不稳定状态。通过边坡修整、砌筑挡土墙及截(排)水沟、防护和绿化工程等工程治理措施后,对坡面稳定性进行了计算,治理后的边坡满足规范要求的稳定安全系数。地质灾害治理工程带来的经济效益、社会效益及环境效益凸显。     

汶川地震灾区影像地图的研制

结合汶川地震期间分县、1:25 000和1:5 000应急影像地图的设计与生产,对一些相关技术进行了试验和总结,可为今后影像地图的研制提供理论和方法上的参考.     

Types and Causes of Debris Flow Damage to Drainage Channels in the Wenchuan Earthquake Area

Debris flows are among the most common geological disasters in China,and have been particularly frequent in Sichuan Province since the Wenchuan earthquake on 12 May 2008.The construction of debris flow drainage channels is a countermeasure used to distribute debris flow fans,and these channels play a critical role in the mitigation and prevention of damage resulting from debris flows.Under field conditions,the useful life of drainage channels can be greatly shortened as a result of strong abrasions to the drainage structure caused by the debris flow.Field investigations have shown that the types of damage to drainage channels include（a） erosion caused by hyper-concentrated silt flow,（b） impact fractures and foundation scour at the groundsills of the drainage channel,（c） destruction of the drainage channel outlet,and（d） destruction of the drainage channel caused by debris flow abrasion.In addition,based on the destruction of the drainage channel during the debris flow drainage process,a new type of drainage channel with energy dissipation components was proposed and applied in a steep,narrow gully for debris flow mitigation.Moreover,design and engineering repair recommendations for drainage channels are provided as a reference for repairing the damage to the channel.The results can provide an important reference for the effective repair and optimal design of drainage channels.     

Impact of the Wenchuan Earthquake on tourism in Sichuan, China

An intensive earthquake, the Wenchuan Earthquake of 8.0 on the Richter scale, struck western Sichuan, China on May 12, 2008. The earthquake has tremendously affected all industries in the quake-hit areas, with no exception ：of the local tourism. The study of the effect of the earthquake on tourism enriches the theory of tourism, and more importantly, it well serves as the foundation for policy making. The objective of this study is to outline for readers the empirical findings on the various ways that the earthquake affected the operations and viability of tourism in the quake-hit areas. This paper is mainly divided into 3 parts. The first part is to discuss the importance of tourism in the quake-hit areas. The second is to analyze the influencing factors of tourism. The third is to assess the impact of the earthquake on tourism in Sichuan in different seasons.     

The genetic mechanism of Wenchuan Earthquake

The genetic mechanism of the 5.12 Wenchuan Earthquake is still being debated and there is still no convincing general explanation for most of the phenomena. This is because researchers have ignored the important role of the Minshan block in the seismogenic process. The authors present a new opinion based on geological survey and comprehensive analyses. The Minshan block is a key tectonic element of the earthquake occurrence in the northwest triangle faulty block of Sichuan Province. The Minshan block is bordered by Longmen Mountain Range fractures in the south, the Huya fracture in the east, the Tazang fracture in the north and the Mounigou Valley fracture in the west. The rigidity of the block is relatively larger than those of the adjacent regions. The block’s eastward movement pushed by regional maximum main geo-stress is limited when it suddenly tapers off near the east triangle end with a bottle-neck effect, and this causes geo-stress concentration around it. The shape of the block is coffin-like, wide in the upper part and narrow in the lower part. When a strong earthquake occurs along the block margins, the lock-up effect temporarily released, resulting in geo-stress transmitted to the Pingwu-Qingchuan (Motianling block) region. This transmission caused the Wenchuan earthquake’s aftershocks to be concentrated in Qingchuan region. As the block moved eastward, the back of the block, i.e. the south segment of Mounigou Valley fracture, became active after the Wenchuan Earthquake. Therefore the aftershocks were concentrated along the south segment of Mounigou Valley fracture. Because the south margin is composed of the front range fracture, the geo-stress gradually released, causing many aftershocks along the Guanxian-Anxian fracture. The geological survey made after the Wenchuan Earthquake reveals that the surface ruptures in the south margin of Minshan block occur not along the Beichuan-Yingxiu fracture (central fracture) also along the front range fracture. The length of the surface rupture in the south margin ranges from several meters to several kilometers and it is distributed in en echelon (closely-spaced, parallel or subparallel, step-like surface ruptures). The vertical and horizontal displacements range from place to place and the thrusting component is dominant in the middle segment of Longmen Mountain Range structure belt. Nevertheless, the strike slip of the surface ruptures is dominant in the north segment of Longmen Mountain Range structure belt. Therefore the south margin is the original seismic structure. The sudden thrusting of the south margin of the Minshan block is the source event for the Wenchuan Earthquake.     

汶川震后龙门山周边活动地块构造变形及断裂活动

利用1999~2013陆态网络观测资料,计算汶川地震前后龙门山地区周边活动地块应变率场分布及欧拉旋转矢量,基于Okada矩形位错模型,反演块体边界主要断层活动性状,分析研究区域现今构造变形和应变分配,并讨论汶川地震对上述过程的影响。研究表明,巴颜喀拉东部、川西北、滇中等活动地块向南东向运移的同时自身作顺时针旋转;由于龙门山断裂、丽江-小金河断裂等逆冲带对地壳应变的吸收与调整,研究区域地壳变形由西向东逐渐减弱,区域地壳变形以连续渐变为主要特征;汶川地震使巴颜喀拉块体、川西北块体的南东向运移加速,并增强了安宁河-则木河-小江断裂带左旋走滑运动和丽江-小金河断裂的逆冲运动。     

Debris Flow Formation Process and Critical Hydrodynamic Conditions in the Meizoseismal Area of the Wenchuan Earthquake

The Wenchuan earthquake generated strong surface disturbances and triggered a large number of loose deposits, resulting in the disasterprone environment with special watershed hydrological characteristics. This paper was to propose a debris flow formation process and explore the permeability characteristics and critical hydrodynamic conditions of the loose deposits triggered by the earthquake. The Guo Juanyan gully(31°05′27″ N to 31°05′46″ N, 103°36′58″ E to 103°37′09″ E) in Du Jiangyan City, located in the meizoseismal areas of the Wenchuan earthquake, was chosen as the study area and the disaster-prone environment was analyzed. The formation process of the debris flow was first proposed using a stability analysis, and then, the permeability characteristics of loose deposits were determined via in situ permeability experiments. Finally, the critical 1 h rainfall was simulated through a distributed hydrological model and verified by field observations. The formation process of debris flow could be divided into three stages based on the relationship between the hydrodynamic force and loose deposit resistance. The critical 1 h rainfall amounts under three antecedent moisture conditions(I-dry, II-normal and III-wet) were 52 mm/h, 43 mm/h and 34 mm/h, respectively. This study proposed a debris flow formation process in the meizoseismal areas of the Wenchuan earthquake based on the stability analysis and defined the rainfall threshold for debris flow early warning at the local level, which is significant for debris flow mitigation and risk management.     

汶川大震的科学思考

在野外地震地质科学考察的基础上,围绕汶川地震发震断层的特征、发震机制、地表破裂带的分段性与分带性、南北构造带地震危险性、地震地质灾害的多发性及链生性、工程建(构)筑物的破坏特征与安全性、地震烈度区划问题及极端自然灾害的预测与应对等进行了分析和讨论,并就有关问题提出了一些新的思考.结果表明,低速滑动断层、晚更新世断层或中央活动断裂也可以发生强震;汶川地震同时具有深部构造的控震作用;地表破裂沿走向可分为映秀-安县段、北川-关口段及青川段;地表破裂可分为主破裂、牵动破裂与感应破裂3种类型;青川段的深部破裂与浅部破裂没有几何上的连续关系或继承关系;贺兰-川滇南北构造带是中国大陆强震多发带,尤其是其北段的六盘山-天水-武都-青川一带未来的强震危险性不容忽视;汶川地震地质灾害具有灾害类型多、成因机理复杂、灾害链长、规模大、范围广、灾害程度深、危害对象广、持续时间长等特点;高烈度区和活断层沿线的地质灾害危险性区划与预测评价对防灾减灾极为重要;活动断裂沿线应注意破裂影响带宽度与建筑物安全避让距离;应对地震等极端自然灾害,应以预防为主,综合减灾;地震烈度区划应同时考虑活动断层的复发周期、地震的离逝时间乃至地形地貌条件;重大工程应提高设防烈度;应当加强极端自然灾害预测评估,完善应对对策和提高应对水平.     

Slope debris flows in the Wenchuan Earthquake area

Avalanches and landslides, induced by the Wenchuan Earthquake on May 12, 2008, resulted in a lot of disaggregated, solid material on slopes that could be readily mobilized as source material for debris flows. Rainstorms triggered numerous slope debris flows with great damage to highways and rivers over the subsequent two years. Slope debris flows (as opposed to channelized debris flows) are defined as phenomena in which high-concentration mixtures of debris and water flow down slopes for short distances to highways and river banks. Based on field investigations and measurements of 19 slope debris flows, their main characteristics and potential mitigation strategies were studied. High rainfall intensity is the main triggering factor. Critical rainfall intensities for simultaneous occurrence of single, several and numerous slope debris flow events were 20 mm/day, 30mm/day, and 90 mm/day, respectively. Field investigations also revealed that slope debris flows consist of high concentrations of cobbles, boulders and gravel. They are two-phase debris flows. The liquid phase plays the role of lubrication instead of transporting medium. Solid particles collide with each other and consume a lot of energy. The velocities of slope debris flows are very low, and their transport distances are only several tens of meters. Slope debris flows may be controlled by construction of drainage systems and by reforestation.     

汶川县麻柳沟泥石流动力学特征及危险性评价

2013年7月10日,四川省汶川县映秀镇境内的麻柳沟流域暴发了大规模的泥石流灾害,给当地人民的生命财产安全造成了巨大的影响。在对麻柳沟流域野外实地调查的基础上,研究了麻柳沟流域泥石流的形成条件与动力学特征,评价了其泥石流的危险性,探讨了它们的发展趋势与防治对策。结果表明:在未来相当长的一段时期内,麻柳沟流域都将处于泥石流活跃期,在雨季强降雨的条件下,发生具有较大破坏力与危害性的中等及较大规模泥石流灾害的可能性仍然较大。因此,提出了生物与工程相结合的防治措施、选取合理的设计参数及提高泥石流的设防标准、加强监测与预警与普及泥石流基础知识等防治对策来减轻该流域的泥石流灾害。      

汶川地震地形形变监测与分析

地形形变监测与分析对于研究汶川地震对震区及青藏板块地形变化的影响有重要意义。通过收集相关监测点的汶川地震前后地形形变数据,采用统一模式进行数据处理,将震前与震后的形变监测成果归算到ITRF2005参考框架和2008.363(2008年5月12日)历元,计算得到震中区域的大地基准造成严重破坏,监测点形变位错,水平位移量达243 cm,沉降量达68 cm,隆起量达36 cm。并对汶川地震地形形变监测进行分析,认为位于"映秀镇—北川—青川"断裂带西侧块体呈现向东南方向移动并呈现隆起趋势;东侧块体向西北方向移动并呈现下沉趋势;北侧块体向东北方向移动,南侧块体向西南北方向移动,块体两侧形成了明显挤压形态。上述研究为进一步揭示汶川地震产生的机理和龙门山断裂带的活动提供了良好基础。