ABSTRACT Slope failure near a reservoir area is mainly influenced by reservoir impoundment and rainfall. In this paper, a bank slope on the Lancang River near a hydropower station in Southwest China is studied. The FEM numerical model is established to investigate the deformation and stability of the bank slope, especially the influence of the reservoir impoundment and rainfall. Unbalanced force (UST) and the factor of safety of the potential failure surface are presented to quantitatively evaluate the monolithic stability of the slope. The numerical analysis results show that the slope reaches a critical state after the first impoundment. The maximum deformation is mainly located at the toe of the slope towards the riverbed. The failure mechanism can be explained that the bank slope especially the toe of the slope is softened by rainfall and water impoundment and the effective stress effect makes it easier for the slope to yield, which results in significant deformation or landslide failure. It is also demonstrated that the toe reinforcement has a significant effect on restraining the shear displacements of the slope and preventing the progressive failure of the landslide. This study presented a feasible approach for more accurate analysis of reservoir slope stability during impounding and rainfall, and also provided practical measures for slope reinforcement. INTRODUCTION Landslides will cause major threat to both lives and property worldwide, especially in regions of steep terrain and heavy rainfall (Xu et al., 2014). Due to the impoundment of many large reservoir dams, more and more landslides have been triggered and cause serious damage. Water is an important factor that influences the mechanical behaviour of geotechnical materials and is responsible for many engineering hazards (Vásárhelyi and Ván, 2006; Wang et al., 2014). The weakening effects caused by water will significantly influence the stability of the reservoir slope.

地质力学模型试验是评价拱坝整体稳定性和加固处理效果的有效手段,采用200:1几何比尺对新疆某高拱坝进行三维地质力学模型试验;模型采用小块体砌筑技术对坝址区不同质量分级岩体的变形、强度特性以及优势节理裂隙进行模拟,基于压缩变形相等的原则模拟断层、岩脉等软弱结构面,并且考虑了建基面槽挖填换混凝土、抗剪洞等加固处理措施;基于油压千斤顶加载系统模拟坝面分布式水载,采用数据采集系统和视频监控系统记录分析坝体及坝基在超载过程中的变形、应力和开裂破坏过程;确立了拱坝起裂安全度K1、非线性起始安全度K2、极限荷载安全度K3三个稳定性评价指标;此外建立数值模型,基于变形加固理论对比分析了拱坝的整体稳定性,确定工程稳定的控制部位和值得注意的薄弱区域.结果表明:拱坝的3个安全度分别为K1=2.0、K2=4.5～6.0、K3=11～12.在超载过程中,河床右岸坝踵破坏程度较左岸严重,断层jef36、jef4局部出现开裂但未见明显错动.整体而言,地基和坝体的破坏程度均较小,整体上是稳定的.

Reservoir bank deformation and reservoir-induced earthquakes have been observed during the impounding of arch dams. Reservoir-induced earthquakes may be precursors of widespread slope deformation, which can endanger the long-term, efficient and safe operation of arch dams. This paper presents an analysis of deformation monitoring data and seismic monitoring data before and after impounding of the Xiluodu arch dam. The results compare the reservoir bank deformation and the seismic activity variations in the reservoir area before and after impoundment which were used to analyze the mechanisms relating the reservoir bank deformation and the reservoir-induced earthquakes. The results show that the two processes are correlated with initially fast responses including hysteresis transitioning to slower responses and then to constant values. The fast response is due to the reduction of the effective stress caused by the mechanical action of the water that leads to irreversible plastic deformation and fault slip. The hysteresis is due to the decreased shear strength of the rock mass and faults due to the physicochemical action of the reservoir water, which leads to slow deformation of the rock mass and the sliding of faults. The correlation between the two phenomena provides a basis for intelligent monitoring and safety warnings of high arch dams during impounding.

高拱坝蓄水期间均监测到一定程度的库岸变形,且变形量值和变形规律不一,这对超静定结构的高拱坝的工作性态和长期安全造成一定程度的影响.本文对白鹤滩拱坝的谷幅变形、坡体内部变形和库盘变形进行统计分析,研究了白鹤滩工程库岸变形的时空分布规律.通过建立谷幅变形的多元逐步回归模型,分离出水位分量、温度分量和时效分量.建立了有限元数值模型,基于裂隙岩体有效应力原理,利用弹塑性有限元方法,计算了白鹤滩拱坝初期蓄水到800 m高程时产生的谷幅变形.监测资料分析表明:大部分测线基本表现为收缩变形,且都与水位的上升具有一定的相关性;从顺河向方向来看,上游侧的谷幅变形值大于下游侧;从断面不同高程上的测线来看,谷幅收缩变形呈现自高而低依次减小的分布规律;坡体内部处于拉伸状态;库盘变形以下沉为主.多元回归分析和数值计算结果表明:谷幅变形监测值与800 m水位下有效应力计算值在上游侧的测线量值较为接近,两者在空间上也具有相同的分布规律,可以认为有效应力改变是初期蓄水库岸变形的主要影响因素.

Mengdigou double-curvature arch dam, located in the southwest of China, is a 200-meter-high dam with complex geological conditions. Failure analysis of the arch dam coupled with the foundation is important for evaluation of the stability. In this regard, a geomechanical model test was carried out. The data pertaining to displacements, stresses, and acoustic emissions, and the entire process of the failure occurring during overloading were obtained. During the overloading process, crack initiates in the upstream dam heel. Then, a crack appears downstream at the dam toe as the load increases. After the damage of the dam toe, cracks occur in the faults around the abutment. Meanwhile, cracks develop rapidly in the arch dam. Eventually, the dam-foundation system loses its ultimate bearing capacity and fails. The results of the model test were compared with those of numerical calculation. Then, the nonlinear deformation and failure mechanism was analyzed. Finally, the safety factor of cracking of the arch dam, the safety factor of the initial nonlinear deformation, and the safety factor of the ultimate bearing capacity were obtained, which reveal that the design of the arch dam is reasonable.

The deformation of mountains induced by reservoirs around high arch dams may influence the safety of those arch dams, but the underlying mechanisms of this phenomenon have not yet been elucidated. The abutment movements of the Jinping-I and Xiluodu arch dams during reservoir impoundment are analyzed systematically in this paper, and the analysis reveals that impoundment led to basin irreversible uplifts. The underlying mechanisms are analyzed from the viewpoint of the constitutive relation of rock mechanics. Based on the theories of poroelasticity and poroplasticity, the effective stress principle of rock is deduced considering the effect of high pore pressure. The modified nonlinear finite element program TFINE is used to simulate the abutment movements of the Jinping-I arch dam, and the calculated values are in accordance with the measured values, verifying the validity of the revised effective stress principle.

金融市场化的发展,带来了新兴业务的有利发展机遇,国内商业银行纷纷开始尝试建立新兴业务的利润中心管理模式.文章基于2009年诺贝尔经济学奖得主威廉姆森(Williamson)新制度经济学中的多部门组织结构理论,通过构建"权责利坐标轴",来分析商业银行经营性职能部门如何向部门制利润中心模式、事业部模式和控股子公司模式进行再造,最后对不同模式进行比较分析,并提出建议.

一、事业部制度的框架:一个历史的 视角 (一)框架 事业部制度是20世纪初期美国大型企业发明并实行的一种管理控制制度,当时以杜邦化学公司和通用汽车公司为典型,因而有“杜邦通用模式”之称,嗣后,风靡美国和世界其他国家,成为管控大型企业(包括大型商业银行)可以效法或借鉴的蓝本. 事业部制度产生的背景是1900年前后美国发生的那场大规模的兼并运动,它直接导致了企业组织形式由工厂为主导转变为以集团公司为主导,使一大批迄今仍然健康运营的大型集团公司如雨后春笋般地发展起来.对一家工厂,其内部管理主要解决效率问题,而对一家集团公司,其内部管理不仅解决效率问题,而且要解决如何将多部门、多工厂(产品或服务)、多层级、多员工整合起来,围绕着集团公司的总体目标而运作(也称多元同心、目标一致或者协同)的问题.