汾渭盆地地裂缝成因研究中的若干关键问题

汾渭盆地是我国地裂缝发育最强烈的地区,地裂缝类型多样,成因复杂。本文概述了汾渭盆地地裂缝的分布规律,分析了目前汾渭盆地地裂缝成因研究中存在的主要问题,重点围绕构造型地裂缝的成因问题,提出如下研究思路:通过多学科联合手段,重点研究汾渭盆地地裂缝灾害的分布规律及其与活动构造的分布关系与成生联系,建立构造地裂缝的地质结构模型;将现代物理数值模拟技术与高精度观测技术相结合,分析研究构造活动启动地裂缝灾害的力学机理以及构造作用与抽水作用耦合致裂机理;以GPS观测资料为约束,将汾渭盆地地裂缝的成生与青藏、华北大陆变形的动力学过程联系起来,研究该区地裂缝与现今中国大陆动力学的内在联系,揭示大陆驱动力产生地质灾害的动力学机制与模式。     

Effects of rainfall infiltration on deep slope failure

With the finite element method and the limit equilibrium method, a numerical model has been established for examining the effects of rainfall infiltration on the stability of slopes. This model is able to availably reflect the variations in pore pressure field in slopes, dead weight of soil, and the softening of soil strength caused by rainfall infiltration. As a case study, an actual landslide located at the Nongji Jixiao in Chongqing is studied to analyze the effects of rainfall infiltration on the seepage field and the slope stability. The simulated results show that a deep slope failure is prone to occur when rainfall infiltration will lead to a remarkable variation in the seepage field, in particular, for large range pore water pressure increase in slopes. Supported by the Knowledge Innovation Project of Chinese Academy of Sciences (Grant No. KJCX2-SW-L1-4) and the Major State Basic Research Development Program of China (Grant No. 2002CB412703)     

抚顺石油一厂地表变形初步探讨

石油一厂地表变形的主要因素是西露天矿露天台阶开采, 引起厂南缘边坡失稳、变形和地面沉陷, 同时促使其它因素活化, 更加剧了地裂缝和变形发展。     

西安地铁二号线沿线地裂缝未来位错量估算及工程分级

地裂缝在地铁设计使用期内的最大垂直位错量是西安地铁二号线穿越地裂缝结构设计的一个十分重要的参数。本文以历史水准监测资料为基础,分析了西安地铁二号线沿线各地裂缝在不同历史阶段的活动特征与活动原因,对各地裂缝的未来活动趋势进行了预测。然后通过基于不同时间段地裂缝活动速率的最大垂直位错量估算结果的对比分析,得出了地铁设计使用期内各条地裂缝与地铁交汇点处地裂缝的最大垂直位错量,并以此为依据,将西安地铁二号线沿线地裂缝分为Ⅰ、Ⅱ、Ⅲ和Ⅳ级等4个工程级别。     

Method to calculate fatigue fracture life of control fissure in perilous rock

Rupture and safety of perilous rock are dominated by control fissure behind perilous rock block. Based on model-Ⅰand model-Ⅱstress strength factors of control fissure under acting of weight of perilous rock, water pressure in control fissure and earthquake forces, method to calculate critical linking length of control fissure is established. Take water pressure in control fissure as a variable periodic load, and abide by P-M criterion, when control fissure is filled with water, establish the method to calculate fatigue fracture life of control fissure in critical status by contributing value of stress strength factor stemming from water pressure of control fissure in Paris's fatigue equation. Further, parameters (C and m) of sandstone with quartz and feldspar in the area of the Three Gorges Reservoir of China are obtained by fatigue fracture testing.     

水泥混凝土路面裂缝成因与质量控制

水泥混凝土路面普遍存在板块裂缝问题.结合常见的几种裂缝形式,分析了产生裂缝的原因,提出了加强多方面综合控制的方法和处理措施.     

基于InSAR的西安地面沉降与地裂缝发育特征研究

哺乳动物细胞胞质分裂过程中伴随着一系列形态学改变,随着分裂沟不断收缩,形成连接两 个子细胞的细胞间桥. 间桥不断拉长、变细,直至断裂、生成两个子细胞. 采用细胞力学 和形态学测量及分析方法,通过施加肌球蛋白II抑制剂,定量研究了NRK细胞间桥变细动力 学; 采用细胞免疫荧光技术, 检测了早期胞质分裂肌动蛋白的分布,揭示肌球蛋白II缺失细 胞胞质分裂可能的机制. 结果表明：施加肌球蛋白II抑制剂的NRK细胞, 其整体形态学和细胞 间桥形态学曲线明显不同于0.3%DMSO组. 根据流体力学特性和所测量的力学参数对曲线 进行模拟发现,表面张力对肌球蛋白II抑制组细胞的间桥动力学曲线轨迹影响很大. 研究结 果提示由细胞力学特性决定的拉普拉斯压力和细胞运动共同参与了肌球蛋白II缺失细胞胞 质分裂的调节.     

Vers une théorie énergétique de la rupture fragile

The drawbacks of the classical theory of brittle fracture, based on Griffith's criterion – a notion of critical energy release rate –, and a fracture toughness k, are numerous (think for instance the issue of crack initiation) and penalize its validity as a good model. Are all attempts at building a macroscopic theory of fracture doomed? The variety and complexity of micromechanical phenomena would suggest that this is indeed the case. We believe however that structural effects still preside over fracture and consequently propose to modify slightly Griffith theory without altering its fundamental components so that it becomes amenable to the widest range of situations. The examples presented here will demonstrate that a revisited energetic framework is a sound basis for a theory which can be used at the engineering level and which reconciles seemingly contradictory viewpoints. To cite this article: G. Francfort, J.-J. Marigo, C. R. Mecanique 330 (2002) 225–233.     

跨地裂缝墙体开裂形态分析

应用非线性有限元法对跨地裂缝的墙体开裂形态进行了分析,确定出了具有三维活动性的地裂缝垂直穿越墙基时,墙体出现裂缝的位置、倾向、倾角和后期的发展状况,以及随沉降量与张开量比值变化的规律。结果表明:地裂缝垂直穿越围墙时,墙体上出现的裂缝一般有两种形式:一是位于地裂缝下盘的墙顶竖直裂缝,二是出现在地裂缝正上方墙体底部的斜裂缝;当地裂缝两盘的土体活动以水平拉张为主时,墙体底部出现的斜裂缝以高角度向上扩展,当地裂缝两盘的土体活动以差异沉降为主时,墙体底部出现的斜裂缝则以较缓的角度向上扩展,倾向与地裂缝相反;只要地裂缝的上下盘土体有微小的错动,一般2～3mm时,就会引起墙体的破裂,且墙体裂缝扩展迅速,几个毫米的错动量,就能使墙体裂缝扩展数十厘米,甚至贯通整个墙体;墙体斜裂缝在产生初期较为平直,随着裂缝的迅速扩展,端部稍向下弯曲,倾角减缓,整体呈弧弯状。     

Une condition de déviation des fissures dans les CMC et les multicouches

A crack deflection criterion is proposed on the basis of the Cook and Gordon mechanism. The stress state induced by a crack was computed in an elementary cell of bimaterial using the finite element method. An interface failure criterion was established in terms of strengths and elastic moduli of constituents. A master curve was produced. It allows matrix crack deflection to be predicted with respect to constituents properties and interface strength. The model can be used also to evaluate the strength of interfaces and interphases in ceramic matrix composites and in multilayers. To cite this article: S. Pompidou, J. Lamon, C. R. Mecanique 333 (2005).