Analytical Solutions for Pore-Fluid Flow Focusing Within Inclined Elliptic Inclusions in Pore-Fluid-Saturated Porous Rocks: Solutions Derived in an Elliptical Coordinate System

Exact analytical solutions have been derived rigorously for the pore-fluid velocity, pore-fluid-flow focusing factor, stream function and excess pore-fluid pressure around and within a buried inclined elliptic inclusion in pore-fluid-saturated porous rocks. The geometric characteristics of the buried inclined elliptic inclusion are represented by the aspect ratio and dip angle of the inclusion, while the hydrodynamic characteristic is represented by the permeability ratio of the elliptic inclusion to its surrounding rock. Since an elliptic inclusion of any aspect ratio can be used to approximately represent geological faults and cracks, the present analytical solutions can be used to investigate the pore-fluid-flow patterns around buried faults and cracks within the crust of the Earth. Therefore, the present analytical solution not only provides a better understanding of the physics behind the pore-fluid-flow focusing problem around and within buried faults and cracks, but also provides a valuable benchmark solution for validating any numerical method in dealing with this kind of pore-fluid-flow focusing problem. The pore-fluid-flow focusing factor of a buried elliptic inclusion is demonstrated to be dependent on the aspect ratio, the permeability ratio and the dip angle.     

软地层中斜拉群锚特性的研究

为了研究上海地区土层锚杆的群锚效应，本文以明德林（Ｍｉｎｄｌｉｎ）解为基础，通过引用根据试验所得的锚杆非线性传递函数，对软地层中斜拉锚杆的长度、间距、入土深度、压浆等因素对群锚效应的影响进行了探讨，得出一些有价值的结果。     

地震波斜入射情形下水平成层半空间自由场的时域计算

在应用有限元模拟地震工程中的波动散射问题时，为了计算边界节点的运动和实现波动能量的输入，必须首先确定边界节点的内行波场即背景水平成层半空间的自由场。利用显式有限差分法的内节点位移计算公式和基于水平成层介质波动传播特点建立的相邻节点间自由场运动的关系式，给出了计算水平成层半空间自由场的时城方程(以入射侧边界节点为例)。本方法是显式有限元意义上的数值精确解，可应用于近场波动数值模拟中内行波场与散射波场的时城同步模拟。     

用相关斜率法初步分析乌鲁木齐04井水位异常特征

地下流体尤其是地壳深部的地下水 ,当它们形成具有一定封闭条件的承压系统时 ,能灵敏地反映地壳的应力应变状态 ,这种深部承压系统近似一“天然应变仪”,从这个角度出发 ,研究地下水的动态变化与地壳应力应变的关系 ,利用相关斜率分析法 ,探讨相关斜率 K值时空演变序列与地震间的关系 ,得出相关斜率具有较好的映震能力 ,且有短期预报效应     

Dynamic response and optimization of an inclined steel rock shed by the graded energy dissipating method

Blocking rockfalls directly by reinforced concrete(RC) flat sheds with thick sand cushions is an outdated method. Such conventional sheds typically accumulate rock heavily, and become progressively damaged and are difficult to repair, and are very costly. To address these problems, we propose a new structure called a Graded Dissipating Inclined Steel Rock(GDISR) shed that utilizes the graded energy dissipation method. Here, we study the dynamic response of the GDISR shed with model test and numerical simulation, and give its optimization design combining with a practical engineering case. Our results show that the optimized modular E-block and corrugated steel tube can deform to sufficiently absorb the energy of different impact intensities. This efficiently and economically provides GDISR sheds with two security lines. Compared with conventional RC sheds, GDISR sheds with optimal incline have a more efficient anti-impact function, are faster and easier to repair, and are much simpler and cheaper to build.     

Maximum Force of Inclined Pullout of A Torpedo Anchor in Cohesive Beds

Torpedo anchors have been used in mooring systems for deep-water oil and gas projects owing to their prominent advantages, such as low cost and easy installation. The maximum force of torpedo anchors is crucial not only to the safety and stability of vessels and other marine facilities, but also for an economical design. It is necessary to develop reliable formula for fast predicting their maximum inclined force of a torpedo anchor in cohesive beds. In this study, the maximum inclined force of a torpedo anchor vertically embedded in cohesive beds was extensively investigated. 316 sets of inclined pullout laboratory tests were carried out for 9 differently shaped torpedo anchors which were vertically embedded in different cohesive beds. The loading curves were automatically acquisitioned and their characteristics were analyzed. The load angle relative to the horizontal varied from 20° to 90°. A new formula for fast calculating the maximum inclined force of the torpedo anchor vertically embedded in cohesive beds was obtained based on force analysis and a nonlinear regression on the data from the present and other studies. Effect aspects on the tests are discussed and further studies are highlighted.     

Using ichnological relationships to interpret heterolithic fabrics in fluvio-tidal settings

In fluvio-tidal settings, the sediment is dominantly derived from the river systems. However, the importance of landward tidal transport of sediment in tidally influenced sedimentary environments is difficult to assess, particularly in the rock record. This problem is addressed using two intervals within the Lower Cretaceous McMurray Formation, each representing a distinct inclined heterolithic stratification motif. The ichnological variation between the heterolithic intervals is analyzed to determine which lithosomes are associated with brackish-water (tidally influenced) colonization windows. From this, the relative fluvial influence responsible for the deposition of the fine and coarse members can be determined. Both of the inclined heterolithic stratification fabrics studied record the deposition of fluvio-tidal point bars wherein the heterolithic bedding represents variations in river discharge. The first fabric comprises inclined heterolithic stratification in which bioturbation only occurs in mudstone beds. This fabric indicates that deposition occurred in more proximal positions within a fluvio-tidal system (i.e. the outermost inner to middle estuary or distributary channels). In this example sand deposition is interpreted to represent high-energy, freshwater dune migration within a fluvial-dominated setting, whereas mud beds reflect brackish-water suspension deposition during times of low river discharge. The second fabric, which is interpreted to have developed in more distal depositional positions (i.e. the middle estuary or seaward of the turbidity maximum in deltas), consists of inclined heterolithic stratification with laminated mudstone and bioturbated sandstone. In these inclined heterolithic stratification successions the mudstone beds were deposited under the influence of freshwater and heightened sedimentation rates, whereas bioturbated sandstone was colonized under brackish-water conditions and in the presence of tidally facilitated sediment transport. In both examples, the bioturbated lithosomes are related to colonization windows that indicate the predominance at that time of marine or tidally influenced processes over fluvial processes.     

基于主应力迹线分层的挡墙被动土压力分析方法

为了探讨墙背倾斜与粗糙程度对挡墙被动土压力的影响,首先,结合被动状态下受挡墙墙背和滑动面摩擦影响的滑动土楔内主应力传递特点,采用圆弧形主应力迹线描述滑动土楔中最大主应力传递规律,并提出了最大主应力迹线几何参数的确定方法;然后,采用沿最大主应力迹线的分层方法将挡墙后滑动土楔划分为若干圆弧形曲线薄层单元,并通过该薄层单元受力分析,依据其静力平衡条件建立了挡墙被动土压力分析新方法。该方法不仅可反映墙土摩擦和墙背倾斜程度对被动土压力的影响,而且有效避免了目前土压力分析方法研究中普遍采用的直线薄层单元难以准确考虑复杂的单元实际受力情况的问题,从理论上确保了新提出的挡墙被动土压力分析方法更具合理性;最后,通过试验、现有同类方法及所提方法分析曲线的对比,表明了新方法的合理性与优越性。就墙背倾斜与粗糙程度对挡墙被动土压力分布及合力作用点高度的影响规律也进行了探讨。     

库水位下降时隔水底板倾斜的层状岸坡中浸润线的解析解

库岸边坡中的地下水对其稳定性起决定作用,然而目前却没有统一的公式用来计算岸坡中的浸润线.为此,根据三峡库区广泛存在的隔水底板倾斜的层状非均质岸坡建立了基本模型,求得了稳定渗流和非稳定渗流两种情况下,库水位下降时岸坡中浸润线的解析解.同时,结合算例进行了分析,证明该方法在实际工程中具有指导意义.     

厚筏刚性基础倾斜值估算

从弹性半空间Boussiuesq解出发,采用有限元法和压缩层地基模型,探索计算厚筏基础倾斜值的方法,计算厚筏基础的不均匀沉降和倾斜值,并利用工程实例进行说明,计算结果与实测结果较吻合。