A temporal model for landslide risk based on historical precipitation

Of the recognized nonsteady-state factors that influence slope stability, probably most critical in many field situations is the character of precipitation and infiltration activity. A groundwater response model used in conjunction with precipitation records can provide a historical catalog of estimated maximum groundwater levels in a particular study area. An extreme-value statistical analysis of this catalog is linked with geotechnical slope stability analyses to provide a landslide hazard model for estimating the probability of slope failure within a given time. This modeling approach can provide meaningful input to risk assessments for landslide mitigation programs and to decision analyses and cost-benefit studies important for land-use planning and resource management.This paper was presented at Emerging Concepts, MGUS 87 Conference, Redwood City, California, 13–15 April 1987.     

深基坑边坡支护方式的现状

根据目前国内边坡支护工作中的主要方式,将深基坑边坡支护按其结构的受力状态和支护的作用原理进行分类,详细论述了各种深基坑边坡支护方式的机制和适用条件,对今后岩土工程的实际工作具有一定的参考作用。     

岩(矿)石中真实矿物组成的计算及矿物化学成分的初步逼近

本文基于线性规划的数学模型,利用岩(矿)石化学分析资料,佐以矿物相的鉴定结果,能准确计算出岩(矿)石中真实矿物组成。在没有矿物化学成分分析数据的情况下,通过迭代、逼进,能同时给出岩矿石的真实矿物组成及矿物化学成分的逼近值,若进一步结合矿物晶体化学原理进行修正,可得出更为准确的结果。线性规划的数学模型还能应用于矿物端员组成的计算,天然及人工系统的物理化学平衡、岩石学混合计算等各个方面。     

基于区间不确定分析方法的边坡稳定性分析

影响边坡稳定性的岩土参数大多具有随机性、模糊性和可变性等不确定性的特点,因此,需要引入不确定性分析模型进行分析。本文在综合分析岩土参数区间性的基础上,将区间分析模型应用于边坡的稳定性分析。通过引用区间数学的思想,运用区间极限平衡法推导出边坡最小安全系数区间,并在此基础上对边坡进行非概率可靠度分析。     

煤矿采空区探测中的瞬变电磁干扰压制

煤田瞬变电磁探测常在人文干扰较强的煤矿周边进行工作,采集到的二次感应场信号大多噪声水平较高,难以开展处理解释工作.为消除野外数据中的电磁干扰,根据衰减曲线形态特征,利用曲线斜率的平均值及方差统计作为干扰判别机制,并参考邻近未受干扰的测点特性,可以快速简便地压制干扰,较好地恢复原始信号.使用该方法对理论数据与实测数据进行了处理解释,结果证明了方法的有效性.将该方法应用于煤矿采空区探测中,压制干扰后的曲线反演解释异常显示出与已知资料高度的一致性,得到了与实际相符的结果.     

含初始缺陷地铁隧道的抗震动力学行为研究

针对含初始缺陷的既有地铁隧道受邻近穿越隧道施工影响的首都地铁隧道工程背景,基于有限差分方法,通过对既有地铁车站结构受邻近隧道穿越后的抗震性能研究,揭示其抗震动力响应机理。结果表明,在邻近隧道穿越影响下,含初始缺陷的既有隧道各薄弱控制点在地震作用下位移和应力动力时程的波动趋势具有相似性,说明衬砌结构是整体运动的,其位移、应力较穿越前均有所增加,边墙和仰拱在穿越后抗震性能影响最大,剪切破坏主要以车站结构周边土体为主,新线穿越后其剪切破坏分布范围有所增大,应进行注浆加固处理,与自身结构刚度相匹配,提高抗震能力。     

Limit state analysis of earthen slopes using dual continuum/FEM approaches

A framework alternative to that of classical slope stability analysis is developed, wherein the soil mass is treated as a continuum and in-situ soil stresses and strengths are computed accurately using inelastic finite element methods with general constitutive models. Within this framework, two alternative methods of stability analysis are presented. In the first, the strength characteristics of the soil mass are held constant, and the gravitational loading on the slope system is increased until failure is initiated by well-defined mechanisms. In the second approach, the gravity loading on the slope system is held constant, while the strength parameters of the soil mass are gradually decreased until well-defined failure mechanisms develop. Details on applying both of the proposed methods, and comparisons of their characteristics on a number of solved example problems are presented. Copyright © 1999 John Wiley & Sons, Ltd.     

Gravity Flow on Slope and Abyssal Systems in the Qiongdongnan Basin, Northern South China Sea

The study of new seismic data permits the identification of sediment gravity flows in terms of internal architecture and the distribution on shelf and abyssal setting in the Qiongdongnan Basin (QDNB). Six gravity flow types are recognized: (1) turbidite channels with a truncational basal and concordant overburden relationship along the shelf edge and slope, comprising laterally-shifting and vertically-aggrading channel complexes; (2) slides with a spoon-shaped morphology slip steps on the shelf-break and generated from the deformation of poorly-consolidated and high water content sediments; (3) slumps are limited on the shelf slope, triggered either by an anomalous slope gradient or by fault activity; (4) turbidite sheet complexes (TSC) were ascribed to the basin-floor fan and slope fan origin, occasionally feeding the deep marine deposits by turbidity currents; (5) sediment waves occurring in the lower slope-basin floor, and covering an area of approximately 400?km2, were generated beneath currents flowing across the sea bed; and (6) the central canyon in the deep water area represents an exceptive type of gravity flow composed of an association of debris flow, turbidite channels, and TSC. It presents planar multisegment and vertical multiphase characteristics. Turbidite associated with good petrophysical property in the canyon could be treated as a potential exploration target in the QDNB.     

浅层地热能开发利用适宜性分区方法研究--以安徽省浅层地热能调查评价为例

通过对安徽省浅层地热能开发利用适宜性分区方法进行研究,提出以浅层地热能资源赋存及技术经济、环境条件为评价因子,以关键因子为必要条件,采用关键因子法、层次分析法及综合指数法进行适宜性分区的方法;该综合评价方法能客观反映评价区开发利用适宜性特征。适宜性分区是贯穿于浅层地热能调查评价工作全过程并指导合理开发利用的重要基础性工作,其分区方法及评价因子选取需要紧密结合实际、因地制宜。     

煤层气井井身结构的地质适应性与优化方法——以黔西地区为例

结合黔西地区煤层群赋存的地质特点和钻井难点,从工程实际和储层保护出发,分析了现有煤层气参数井、预探井井身结构的地质适应性,划分出4种地层(含煤体)结构条件;提出了不同条件下设计与施工优化的4类8种配套井身结构变化形式,并对其优缺点和适用范围进行了分析评价,以期为复杂地质条件下煤层气探井的井身结构设计提供新的思路。