河流阶地的形成及其对构造与气候的意义

河流系统演化是一个堆积与切割相互作用的过程。通过对河流阶地成因的研究,指出气候成因阶地的堆积主要发生在冰期,其他时期虽有堆积,但保存下来的较少;切割作用发生在冰期一间冰期的过渡期。构造成因阶地切割作用发生的时段就是构造运动的时期,也是古河床开始废弃的时期,提出了判定不同成因河流阶地的地质学特征。气候成因阶地每一级都说明有一个或多个冰期一间冰期的旋回,构造成因阶地的每一级都表示有一期较强烈的构造事件,有些阶地是构造与气候共同作用的结果。     

南黄海新构造运动

定义了南黄海新构造运动的概念;提出了南黄海新构造运动的研究方法;阐明了南黄海新构造运动的机理,即受滨西太平洋构造域控制,是在老构造基础上的继承和发展;描述了南黄海新构造运动的基本特征;总结了南黄海新构造运动的研究意义。     

大洋富钴结壳实时开采切削深度优化分级模型研究

根据统计分形理论对大量实验测得的微地形数字高程数据进行了分维空间、无标度区和分形维数等分析和计算,并求出了各自的地形特征数据,同时建立了单个微地形在控制废石混入率时富钴结壳开采的最优切削深度的遗传寻优算法。在此基础上,利用实验所得各种分形特征数据及微地形的自相似性、各向异性及分形布朗函数,通过计算机自动生成了大量仿真微地形,并求出了各相应仿真微地形的地形特征数值和在控制废石混入率时富钴结壳开采的最优切削深度,再通过对此大样本的统计回归分析,建立了大洋富钴结壳实时开采切削深度的优化分级模型。该模型经实验数据的验证,其结果达到了满意的要求。     

塔里木河下游地下水化学特征对生态输水的动态响应

1IntroductionAs an indispensable part of water resource, groundwater plays an important role in ecological environment. Especially in arid and semi-arid area, the changes of groundwater chemistry even determine the ecological process (Ji, 2001; Murgai, 20…     

地震断层粘滑错动对青藏铁路变形效应的有限元分析——以东昆仑活动断裂为例

东昆仑断裂是青藏高原北部现今仍在强烈活动的左旋走滑地震断裂之一,该断裂的未来地震活动及其突发性粘滑错动是青藏铁路面临的重大工程地质问题.本文基于断裂几何学和运动学特征,通过加入8m的水平左旋位移,模拟了东昆仑断裂未来地震活动震中位于铁路线附近时铁路变形效应.结果表明,震中位于铁路线附近时,基岩整体移动,而第四纪松散层和道床则发生了变形,靠近断裂带附近的第四系自下而上水平位移明显减小,而铁轨和道床没有明显的断错,表现为长度约为25m的连续左旋弯曲变形;在铁路东、西两侧形成NE向的张裂陷和NW向的地震鼓包.在断裂带附近,铁轨发生了严重扭曲,铁轨应力自断裂带向两侧逐渐降低,而且铁轨的最大剪应力平面与铁轨的延伸方向垂直,因而在地震影响下,铁轨最有可能发生的破坏是剪切性的,并提出加宽路基、置换土层等工程防治措施.      

风沙运动理论体系的创建与研究

确定风、沙源、风沙流、下垫面和沙地地表形态是构成风沙运动体系的5个基本要素。确定风速的强弱、沙粒的走停、气流含沙量的盈亏、下垫面的扬抑作用和沙地地表的蚀积变化是这些基本要素各自参与风沙运动的主要表现特征。这些表现特征都能一分为二, 于是10个对立侧面的相互作用构成了风沙运动发展变化的总体。系统地研究这些侧面的组合关系、揭示它们相互促进相互制约的演变机理, 进而依其内在联系进行排序, 将其串联成一体, 并绘出图式, 这样便形成了名之曰"强、弱、扬、抑、走、停、盈、亏、蚀、积十纲辩证"的风沙运动理论体系。其中"强、弱、走、停、盈、亏、蚀、积八纲辩证"是本理论体系的核心。     

用GPS 资料分析渭河盆地及邻近地区地壳运动特征

利用中国地壳运动观测网络工程1999 ~ 2002 年渭河盆地及邻近地区GPS 观测资料, 以及陕西省地震局2001 ~ 2002 年的GPS 观测资料, 研究了渭河盆地及邻近地区地壳运动速度场。结果表明, 渭河盆地及邻区的运动速率有明显的WE 向条带状变化特征, 鄂尔多斯块体南缘呈整体不连续性逆时针旋转运动, 相对鄂尔多斯块体内部的榆林测点, 平均速率约为5.7mm/ a;渭河盆地中部的彬县— 西安— 蓝田一线两侧存在一个左旋剪切带( 东侧) 和右旋剪切带, 左旋剪切带的北部区域与铜川— 泾阳— 临潼— 渭南小震频发区恰好对应;鄂尔多斯块体东南缘临汾盆地东侧, GPS 观测点资料表现出应力集中的迹象, 该区与临汾-韩城地震带也有较好的对应关系。     

Analytical model for the prediction of building deflections induced by ground movements

The objective of this study is to develop an analytical model that can predict the building‐relevant deflections induced by tunnelling or mining subsidence. The model takes into account soil–structure interactions due to differences in stiffness between the ground and the building. The ground is modelled by the Winkler model with an initial ground curvature equivalent to the free‐field ground movements. The building is modelled by a horizontal beam with uniform loading. The static and cinematic equilibrium of both the ground and the building are then calculated to assess the final building and ground shape, and the building deflection is derived. The resulting analytical model is used to investigate the influence of the ground and the building's mechanical properties, the building load and the initial value of the free‐field ground curvature (hogging or sagging). The model appears to be more comprehensive than those reported elsewhere that address the problem with numerical models. In particular, the analytical model makes it possible to distinguish two different final situations—with continuous or discontinuous contact between the ground and the building. The model is compared with numerical results and used to analyse a case study. Copyright © 2010 John Wiley & Sons, Ltd.     

Lateral soil–pipeline interaction in sand backfill: Effect of trench dimensions

Current analytical methodologies for the evaluation of soil pressures on laterally displaced pipelines, as in the case of differential (e.g. fault-induced) permanent ground movements, allow the use of sand fill material properties under the condition that the size of the trench is adequate so that the failure surface develops fully within the sand fill (i.e. “free field” response). The accuracy of this assumption is investigated in this paper by means of numerical analyses, which employ a number of advanced features, such as pipe-backfill interface elements, large strain formulation and mesh rezoning. Following verification against well-documented experimental data, the analyses investigate: (a) the shape and size of the failure mechanism, as well as, (b) the potential trench effects on soil pressures and pipeline strains in the case of a strike-slip fault rupture. It is shown that for small embedment depths soil failure extends to the ground surface, in the form of a general shear failure mechanism, while for larger depths it becomes progressively localized and surrounds the pipeline. It is also shown that, for most cases of pipeline diameter and embedment depth, common trench dimensions cannot contain the “free field” failure surface dimensions. Finally, analyses for limited trench dimensions, reveal that the ultimate soil pressure increases exponentially with decreasing trench width, leading to high bending strains in pipelines subjected to differential lateral ground displacements.     

石花洞8层溶洞展示北京西山新构造运动的隆升

北京大石河南岸从上游至下游依次分布鸡毛洞、银狐洞、石花洞、清风洞和孔水洞,由一条地下暗河将其连为一体,称为石花洞系。石花洞系为多层溶洞,可分为上下8层,即洞外山顶穿洞（唐县期）和洞穴上下7层。多层溶洞的每一层形成于岩溶水的水平流动带,新近纪以来,随着北京西山间歇性隆升,形成上下不同海拔高度的8层溶洞,可以和北京西山永定河的8级阶地对比,也可以和G．B．Barbour划分的8次华北地文期对比。石花洞的8层溶洞显示北京西山的8次抬升。