桐柏山L构造岩形成机制构造解析及其对造山带演化的制约

桐柏杂岩中发育一套典型的L构造岩,其构造位置位于桐柏造山带核部,被两条近似对称的韧性剪切带所夹持,北侧剪切带左旋,南侧剪切带右旋。由于L构造岩构造位置特殊,其位于剪切带、桐柏背形、桐柏穹窿等多种构造体的交叉部位,L构造岩的构造成因解析可以为桐柏造山带的形成演化提供重要制约。通过对桐柏造山带L构造岩的构造成因机理解析和其变形温压条件的研究,同时结合前人对桐柏山其它主要构造单元的研究,我们提出,桐柏山L构造岩的形成主要受其南北两侧两条韧性剪切带控制,传统意义的桐柏杂岩体白垩纪之前与南北一体的韧性剪切带沿近似东西方向发生管状韧性剪切,剪切作用形成了一套典型的L构造岩。L构造岩的形成指示了桐柏山单元可能经历了一期中下地壳物质的管状的韧性的向东剪切流动,后期白垩纪桐柏山核部的L构造岩经历了大规模的岩浆上升与浮力增加,该L构造岩同剪切带一起发生隆升但管状剪切构造特征并未被改造,随着不均匀隆升桐柏山出现了现今的几何学特征。L构造岩反映出管状剪切形成了现今桐柏造山带近东西向线状构造样式的主体。     

2012年7月下旬河套地区4次切变暴雨的对比分析

应用日常预报业务中可以方便使用的常规观测资料、数值预报产品、卫星云图、加密自动站观测资料以及雷达资料等,从环流背景、流型配置、物理机制等方面对比分析了河套地区4次暴雨过程,旨在提高对暴雨的短期预报预测能力及短时强降水的临近预警能力。分析发现：（1）副热带高压西侧的偏南气流以及来自孟加拉湾的暖湿偏南气流在35°—40°N与来自高纬度的干冷的偏北气流多次交汇,水汽在该带中明显辐合,为河套地区持续性暴雨发生发展提供源源不断的水汽,提供水汽辐合上升动力条件;（2）暴雨落区与低层的显著流线出口区或急流出口区的位置、切变线的位置密切相关,暴雨一般落在高空急流的右侧、低空急流的左侧;（3）暴雨天气出现前一般会出现500 hPa以下θ随高度的增加而减少的特征;（4）暴雨天气出现前一般都会出现风随高度顺转的特征;（5）暴雨过程中地面辐合线起到动力抬升作用,触发中小尺度系统的生成和发展;（6）抬升凝结高度和自由对流高度都比较低,利于水汽凝结,而平衡高度较高,利于能量的积累,对于对流天气的预报有较好的指示意义。     

中天山东部南北两缘韧性剪切带变形特征

(1)中天山北缘韧性剪切带除右旋韧剪变形之外,还发育相对较弱的左旋韧剪变形,局部残留加里东晚期的逆冲推覆韧剪变形;右旋韧剪变形的变形温度环境为中-低温,左旋韧剪变形的变形温度环境为高温、中温、中低温及低温。(2)中天山南缘韧性剪切带以右旋韧剪变形为主,兼具左旋韧剪变形;右旋韧剪变形的变形温度环境为中温、中低温、低温,左旋韧剪变形的变形温度环境为高温、中温、中低温及低温。(3)东天山存在一系列右旋韧性剪切带,中天山南北两缘韧性剪切带的构造变形与辛格尔断裂、兴地断裂等右旋韧性剪切带的变形以及塔里木北缘东部晚震旦—早古生代地层的同劈理褶皱变形、南天山泥盆纪地层的变形可能具成因联系。     

Analytical and empirical models for predicting the drift capacity of modern unreinforced masonry walls

Displacement‐based seismic assessment of buildings containing unreinforced masonry (URM) walls requires as input, among others, estimates of the in‐plane drift capacity at the considered limit states. Current codes assess the drift capacity of URM walls by means of empirical models with most codes relating the drift capacity to the failure mode and wall slenderness. Comparisons with experimental results show that such relationships result in large scatter and usually do not provide satisfactory predictions. The objective of this paper is to determine trends in drift capacities of modern URM walls from 61 experimental tests and to investigate whether analytical models could lead to more reliable estimates of the displacement capacity than the currently used empirical models. A recently developed analytical model for the prediction of the ultimate drift capacity for both shear and flexure controlled URM walls is introduced and simplified into an equation that is suitable for code implementation. The approach follows the idea of plastic hinge models for reinforced concrete or steel structures. It explicitly considers the influence of crushing due to flexural or shear failure in URM walls and takes into account the effect of kinematic and static boundary conditions on the drift capacity. Finally, the performance of the analytical model is benchmarked against the test data and other empirical formulations. It shows that it yields significantly better estimates than empirical models in current codes. The paper concludes with an investigation of the sensitivity of the ultimate drift capacity to the wall geometry, static, and kinematic boundary conditions.     

Shear Alteration, Mass Transfer and Gold Mineralization: An Example from Jiaodong Ore Deposit Concentrating Area, Shandong, China

Since Ramsay and Graham (1970 ) system atically deliv-ered study results of ductile shear zone,the study on shearzone has been put forward rapidly and has obtained greatachievements.After the“gold- bearing shear zone” type ofmetallogenic model proposed by Bonnemaison(1986 ) ,lots ofstudies showed that large gold- bearing shear zone system,which underwent multi- stage and multi- level tectonic- m inerl-ization evolution,is a complex deformational metam orphic ge-ological body with different d…     

高层建筑坍塌墙体修复施工安全管理定量化控制模型研究

为了确保震后高层建筑坍塌墙体修复工程的安全性,提出一种高层建筑震后坍塌墙体修复施工安全管理方法。结合主成分分析法与信息熵法对震后高层建筑坍塌墙体修复施工管理的控制特征量进行提取,确定模型评价指标权重;根据加权学习法对坍塌墙体修复的施工进行量化控制;通过灰阶量化评估进行约束参量分析,构建安全管理控制模型;采用管理因素模糊调度算法实现施工安全管理控制,并完成优化决策。通过仿真实验验证坍塌墙体修复施工管理控制的管理效益与累积评价百分率。分析结果表明,采用该方法进行震后高层建筑坍塌墙体修复施工管理控制的管理效益最高可达83.32%,累积管理效果回报率较高,累积评价百分率平均约为75%,能够有效提高施工过程的安全管理效能,确保施工安全。     

供水管井允许出水量的合理确定

每一眼管井在井结构确定的条件下,有一个最大允许出水量,而盲目追求增大出水量,势必造成管井涌砂,过滤管腐蚀和堵塞的加剧。松散含水层供水管井允许出水量既要满足地下水允许开采量“宏观”定义要求,从供水管井使用寿命考虑又要满足管井两个流速参数:井壁允许进水流速和滤管允许进水流速。本文给出了管井允许出水量确定方法和计算框图,并以实例说明之,在具体应用时某些细节也予以了说明。     

砂土的抗剪强度与干密度的曲线拟合

利用曲线拟合的最小二乘法原理，确定砂土在某垂直压力下的抗剪强度与干密度的关系，并绘制曲线图，可避免人工处理数据的随意性，减小了误差。     

Evaluating a process‐based model for use in streambank stabilization: insights on the Bank Stability and Toe Erosion Model (BSTEM)

Streambank retreat is a complex cyclical process involving subaerial processes, fluvial erosion, seepage erosion, and geotechnical failures and is driven by several soil properties that themselves are temporally and spatially variable. Therefore, it can be extremely challenging to predict and model the erosion and consequent retreat of streambanks. However, modeling streambank retreat has many important applications, including the design and assessment of mitigation strategies for stream revitalization and stabilization. In order to highlight the current complexities of modeling streambank retreat and to suggest future research areas, this paper reviewed one of the most comprehensive streambank retreat models available, the Bank Stability and Toe Erosion Model (BSTEM), which has recently been integrated with several popular hydrodynamic and sediment transport models including the Hydrologic Engineering Center's River Analysis System (HEC‐RAS). The objectives of this paper were to: (i) comprehensively review studies that have utilized BSTEM and report their findings, (ii) address the limitations of the model so that it can be applied appropriately in its current form, and (iii) suggest directions of research that will help make the model a more useful tool in future applications. The paper includes an extensive overview of peer reviewed studies to guide future users of BSTEM. The review demonstrated that the model needs further testing and evaluation outside of the central United States. Also, further development is needed in terms of accounting for spatial and temporal variability in geotechnical and fluvial erodibility parameters, incorporating subaerial processes, and accounting for the influence of riparian vegetation on streambank pore‐water pressure dynamics, applied shear stress, and erodibility parameters. Copyright © 2016 John Wiley & Sons, Ltd.     

Vorticity analysis of the Palmi shear zone mylonites: new insights for the Alpine tectonic evolution of the Calabria–Peloritani terrane (southern Italy)

New microstructural data on the mylonites from the well‐exposed Palmi shear zone (southern Calabria) are presented with the aim to shed light on both the kinematics and the geometry of the southwestern branch of the Alpine belt during Eocene. In the study area, located between the Sardinia–Corsica block and the Calabria–Peloritani terrane, previous large‐scale geodynamic reconstructions suggest the presence of strike–slip or transform fault zones dissecting the southwestern branch of the Alpine belt. However, there are no field data supporting the occurrence of these structures. This paper uses vorticity analysis technique based on the aspect ratio and the long axis orientation of rigid porphyroclasts in mylonitic marbles and mylonitic granitoids, to estimate the contribution of pure and simple shear of deformation during the movement of the Palmi shear zone. Porphyroclasts aspect ratio and orientation were measured on thin sections using image analysis. Estimates of the vorticity number, W_m, indicate that the Palmi shear zone recorded general shear with a contribution of pure shear of c. 65%. Then, the Palmi shear zone can be interpreted as a segment of a left‐lateral transpressive bend along the southern termination of the Eocene Alpine front. Copyright © 2015 John Wiley & Sons, Ltd.