辽北法库韧性剪切带变形及其区域构造意义

晚古生代—早中生代古亚洲洋板块俯冲华北板块在辽北法库地区形成大型产状近水平的韧性剪切带.剪切带发展伴随着多期幔源及壳源的岩浆侵入,侵入岩在韧性剪切作用下发生韧性变形,记录了韧性剪切带变形历史.详细的野外地质调查结合岩石的宏观变形、显微构造及石英c轴组构特征分析,揭示了法库韧性剪切带内五龙山杂岩、高丽沟杂岩、早期十间房超...     

碳酸盐岩的声波特性研究及其应用

基于岩溶地区碳酸盐岩试样室内声波测试分析发现: ( 1)泥质灰岩和角砾状灰岩的波速比普通灰岩、灰质白云岩比一般白云岩和角砾白云岩的高。( 2)灰岩的声波、密度略大于白云岩的声波、密度,灰岩的动弹性模量、剪切模量和体积模量也比白云岩大。( 3)溶蚀程度和微小结构面对碳酸盐岩中波的传播速度影响较大,灰岩波速随风化程度的提高而降低。( 4)纵、横波速与岩石的密度具有线性关系,利用密度、波速、纵横波速比或泊松比可初步判断碳酸盐岩在岩性上的差别。( 5)声波测试和单轴抗压强度试验求得的岩石的弹性模量具有一定的相关性,利用声波测试结果可以推求实际工程中计算、设计所需的力学参数。      

Construction and post-construction behaviour of a geogrid-reinforced steep slope

A geogrid reinforced steep slope was built and monitored during construction and during the first ten months of service. The slope is located between Régua and Reconcos in the new Portuguese main itinerary, IP3, and is a part of reestablishment 2. The reinforced slope has an extension of about 206.2m, is in curve and the reinforced area reaches a maximum height of about 19.6m in the outside curve slope at 150.0m of extension (km 0+150). The monitored slope cross section is at km 0+150. The reinforcements are high density polyethylene geogrids;. materials with different tensile strength values were used. The reinforcement strains were measured at three reinforcement levels using linear extensometers. The soil vertical stresses were recorded using load cells. The internal horizontal displacements of the slope were recorded using two inclinometer tubes. The face displacements were recorded topographically in points spaced approximately 1.2m vertically along the face of the slope on the km 0+150 cross section. The reinforced slope behaviour was observed during a period of about 13 months, which includes three months of construction period. This way it was possible to obtain information about the slope behaviour during and after construction (the first 10 months of service). The behaviour of the observed reinforced slope is characterized by: low values of face displacements, slope internal horizontal displacements and reinforcement strains; change of the face displacements configuration at the end of construction during service;tendency to stabilization of the horizontal displacements in a relatively short period of service; change, during service, of the position of the line passing through the points of the reinforcements where maximum strains were recorded. The reinforced slope behaviour express the conservative design of Equilibrium Limit methods and encourage the research on new design methods for geosynthetic reinforced soil systems.     

大规模超长群桩基础工作性能的数值模拟

超长桩基础在土木工程中的应用越来越多,但对其工作性状的研究相对滞后。以某超长群桩基础工程为例,用三维非线性有限元方法分析了超长单桩及群桩的工作性能。计算中桩、土和承台的有限元模型均用8节点六面体等参单元,桩-土界面用有厚度的接触面单元模拟;混凝土的应力-应变关系用线弹性模型,土体用非线性Duncan-Chang弹性模型模拟;承台施工过程用分级加荷的方法模拟,承台混凝土的硬化过程用变化模量的方法模拟。计算结果表明,超长单桩的承载性状属摩擦桩,其桩身失稳的原因是桩侧土体的破坏;在群桩基础中,不同位置基桩的工作性能不完全相同,承台周边桩的工作性能与单桩类似,而与内部桩的差别较大;现行规范中推荐的群桩效应系数和有限元计算结果间存在较大差别,表明现行规范可能不适用于超长群桩基础,对超长群桩基础的工作性能进行深入研究是必要的。     

低信噪比海底多分量地震数据波场分离方法

以多分量地震观测为基础,联合纵波和转换横波数据能更有效地估计地下介质的弹性和物性参数,提升地质构造成像与油气储层描述的精度.在海底多分量地震数据处理过程中,观测记录的上-下行波分解和P/S波分离可压制水层鸣震以及P与S波之间的串扰,对偏移成像和纵横波速度建模至关重要.但受海底环境、仪器与观测因素共同影响,许多海底多分量...     

近场地震动特性及其弹性与塑性谱的研究

结构在近场地震动作用下的反应和远场地震动作用下的明显不同,这主要是由近场地震动高能量的速度脉冲等特征决定的。通过对110条近场地震动记录的分析．得到了相应的弹性反应谱,并通过对近场地震动和远场地震动作用下结构塑性分析进行对比．得到了以下结论：近场地震动作用下结构的弹性反应谱与规范谱明显不同,尤其在长周期阶段,表明规范谱值偏小;近场地震动作用对结构提出了更高的强度和变形需求。     

A rigorous Hamiltonian approach to the rotation of elastic bodies

When the problem of the rotation of a non-rigid body is studied, the usual procedure consists of adding perturbations to the Hamiltonian of the rigid solid. In some cases, as occurs with the centrifugal deformation, the new perturbations contains potentials which depend on the velocity, but usually one alter neither the definition of the canonical variables nor the method for obtaining the Hamiltonian. Although this procedure gives good estimates and its formulation is simpler, it is incorrect from a theoretical point of view.In this paper we rigorously develop a Hamiltonian formulation of the problem, considering potentials that depend on the velocity. Thus the differences between the two procedures are clearly shown, giving special emphasis to the case of the elastic Earth, for which we show that the differences obtained cannot be ignored within the accuracy limits at present required.     

陶庄矿山诱发塌陷地震对承压井水位的影响

试用弹性理论和地下流体动力学分析了陶庄矿山诱发塌陷地震对承压井水位的影响,分析了井水位变化与陷地震震级及塌陷点距水地蝇距离之间的关系,通过对塌陷地震序列的分析,给出了较大塌陷地震前小塌陷地震增多的可能“前兆”。     

弹性波数值模拟的非规则网格差分法

基于应力、速度混合变量弹性波方程及任意四边形网格差分算子,给出了交错计算应力及速度的非规则网格弹性波应力一速度差分法该方法融合了有限元法能适应复杂形状边界及差分法无需计算刚度阵的特点,具有较高的计算精度,所需计算机存储空间较少,计算效率也很高．基于积分平衡方程引入了任意形状自由表面的边界条件,且通过局部滤波改善了自由表面边界条件的稳定性,使得该方法可应用于考虑地表形状影响的地震波数值模拟     

煤中铬的研究现状

对煤中铬的地球化学行为,分布,赋存形式,富集机理,迁移规律等方面的研究现状进行了综述。