改进的双参数层状地基模型   总被引：8，自引：3，他引：5  

高广运  邱畅  王贻荪 《岩土力学》2003,24(2):159-163

文克尔地基模型广泛应用于弹性地基梁、板的设计计算,但由于该模型过于简化,不能正确反映地基土的工程性质。为此,提出了一种改进的双参数层状地基模型。该模型是Vlazov模型的延伸和发展,由一系列的弹性层组成,对每一层的应力应变分布做了一定的假设。通过积分变换的方法,可以求出该模型每一层表面位移与力的关系,进而形成层刚度矩阵。按照有限元法的原理,将每一层的刚度矩阵凝聚成总体刚度矩阵求解,与Vlazov模型计算结果的比较,证明该方法是正确的,还得到了荷载作用于层状地基模型内部的解,为双参数层状地基模型用于桩基分析打下了理论基础。  相似文献   

加筋效应对群桩相互作用系数的影响   总被引：5，自引：2，他引：3  

梁发云  陈龙珠  李镜培 《岩土力学》2005,26(11):1757-1760

群桩相互作用系数通常是采用平面应变模型进行分析,其研究方法具有较多的近似性。基于更为严格的虚拟桩模型,应用群桩相互作用的积分方程解答,以两桩相互作用的基本模型为例,研究加筋效应对群桩相互作用的影响。与弹性理论法和Mylonakis & Gazetas解答的对比表明,加筋效应对群桩相互作用系数有着较为明显的影响,并指出Mylonakis & Gazetas基于剪切位移法所得解答中存在的一些主要问题。  相似文献   

填充沟屏障远场被动隔振三维分析   总被引：6，自引：0，他引：6  

高广运  李志毅  邱畅 《岩土力学》2005,26(8):1184-1188

把填充沟看作存在于弹性半空间的异质体,运用瑞利波散射的积分方程,对填充沟连续屏障远场被动隔振进行了三维分析,详细讨论了影响隔振效果的几个主要参数。研究表明,刚性材料比柔性材料具有更好的隔振效果,在隔振设计时应选择刚性屏障材料;填充沟的深度在一倍瑞利波波长内对隔振效果有较大影响,并且与宽度一起决定其隔振效果,但当屏障深度超过一倍瑞利波波长后,屏障深度对隔振效果的影响很小。  相似文献   

Integral equation solution for three-dimensional heat transfer in multiple-fracture enhanced geothermal reservoirs     

Dong Dong Liu  Yan Yong Xiang  Jin Lei Zheng 《国际地质力学数值与分析法杂志》2020,44(11):1511-1524

For the prediction of energy production from multiple-fractured geothermal reservoirs, previous models basically focused on the one-dimensional conduction in the rock containing evenly distributed fractures of equal scale. Here, a novel model is described to numerically investigate the three-dimensional heat transfer in geothermal reservoirs with unevenly spaced disc fractures of various sizes including the aperture and radius. In terms of the water flow through each fracture, an approximate analytical solution is obtained on the assumption that the water pressure disturbances, induced by the fracture margin and extraction (injection) operation, at the injection (extraction) well center and at different locations within the injection (extraction) well range were approximately equal. By the integral equation scheme for two-dimensional planar fractures, the three-dimensional problem of heat exchange is simulated without the reservoir discretization. The singular integral is analytically calculated in polar coordinates whereas the nonsingular integrand is numerically estimated by the Gaussian quadrature method in Cartesian coordinates. Compared with the one-dimensional simplification, the three-dimensional heat conduction remarkably alters the prediction of extraction temperature. In addition, the reservoir temperature field is also significantly influenced by the spacings and dimensions of fractures. The present model may be used for the estimation, design, and optimization of a geothermal reservoir.  相似文献   

Axisymmetric interaction of a rigid disc with a transversely isotropic half‐space     

Amir Aabbas Katebi  Ali Khojasteh  Mohammad Rahimian  Ronald Y. S. Pak 《国际地质力学数值与分析法杂志》2010,34(12):1211-1236

A theoretical formulation is presented for the determination of the interaction of a vertically loaded disc embedded in a transversely isotropic half‐space. By means of a complete representation using a displacement potential, it is shown that the governing equations of motion for this class of problems can be uncoupled into a fourth‐order partial differential equation. With the aid of Hankel transforms, a relaxed treatment of the mixed‐boundary value problem is formulated as dual integral equations, which, in turn, are reduced to a Fredholm equation of the second kind. In addition to furnishing a unified view of existing solutions for zero and infinite embedments, the present treatment reveals a severe boundary‐layer phenomenon, which is apt to be of interest to this class of problems in general. The present solutions are analytically in exact agreement with the existing solutions for a half‐space with isotropic material properties. To confirm the accuracy of the numerical evaluation of the integrals involved, numerical results are included for cases of different degrees of the material anisotropy and compared with existing solutions. Further numerical examples are also presented to elucidate the influence of the degree of the material anisotropy on the response. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Vectorized simulation of groundwater flow and contaminant transport using analytic element method and random walk particle tracking          下载免费PDF全文

Partha Majumder  T.I. Eldho 《水文研究》2017,31(5):1144-1160

Groundwater contaminant transport processes are usually simulated by the finite difference (FDM) or finite element methods (FEM). However, they are susceptible to numerical dispersion for advection‐dominated transport. In this study, a numerical dispersion‐free coupled flow and transport model is developed by combining the analytic element method (AEM) with random walk particle tracking (RWPT). As AEM produces continuous velocity distribution over the entire aquifer domain, it is more suitable for RWPT than FDM/finite element methods. Using the AEM solutions, RWPT tracks all the particles in a vectorized manner, thereby improving the computational efficiency. The present model performs a convolution integral of the response of an impulse contaminant injection to generate concentration distributions due to a permanent contaminant source. The RWPT model is validated with an available analytical solution and compared to an FDM solution, the RWPT model more accurately replicates the analytical solution. Further, the coupled AEM‐RWPT model has been applied to simulate the flow and transport in hypothetical and field aquifer problems. The results are compared with the FDM solutions and found to be satisfactory. The results demonstrate the efficacy of the proposed method.  相似文献   

整体式止屈器数值模拟方法与优化研究     

颜铠阳  余建星  余杨  韩梦雪  许伟澎  张春迎 《海洋工程》2020,38(6):77-85

海底管道是海洋石油主要的运输方式，但海底管道在外部静水压力作用下很可能发生局部屈曲压溃，造成灾难性后果。安装止屈器可有效阻止屈曲传播，保证管道安全，整体式止屈器在实际中应用最为广泛。整体式止屈器存在通过减小止屈器体积以节约成本进行优化的可能性，因此，在保证止屈器止屈效果的前提下，可通过减小止屈器的体积，以达到减轻重量、节约成本、减少安装难度等多种目的。研究过程中使用ABAQUS进行模型的仿真模拟，比较了广义弧长法的优缺点，决定选用更方便的静水流体单元法，计算得到不同止屈器的穿越压力以及相应的体积，对比各止屈器的穿越压力变化和体积变化，实现结构优化的目标。基于以上研究，可以得出减少止屈器体积的结构优化方案具有可行性的结论。  相似文献   

基于单轨道OT DInSAR的矿山时序三维多量级形变重建     

张乐乐  刘波  贾世利  常英豪  王佳冰  魏增明 《大地测量与地球动力学》2021,41(9):886-894

提出一种矿山地表时序三维多量级形变重建方法。首先利用单轨道OT和DInSAR技术提取LOS向非连续的多量级形变;再结合形变先验融合模型和概率积分法构建矿山三维多量级形变重建模型;最后以神东大柳塔矿山52303工作面为研究对象,对覆盖研究区的6对高分辨率TerraSAR-X数据进行时序处理,获取长时间序列的矿山地表三维多量级形变监测结果。与水准测量结果对比发现,该方法与水准测量结果形变趋势一致,垂直向、东西向和南北向的均方根误差（RMSE）分别小于0.188 0 m、0.224 3 m和0.207 4 m。该方法不仅能准确测量矿山地表三维多量级形变,还能精细反演矿山地表沉降漏斗边缘到中心的形变特征。  相似文献   

几个能量法获取地球重力场模型的关键技术分析     

潘元  方亿锋 《测绘与空间地理信息》2014,(5):214-218

介绍了能量法恢复地球重力场的基本原理,并分别给出了在笛卡尔坐标空间、极坐标空间内的能量守恒公式,探讨了能量常数精度、计算方式与地球重力场反演精度的关系,并通过数值试验进行了计算分析。计算结果表明:对于低轨卫星,在不同坐标空间内转换引起的轨道误差为10-10m量级,对恢复地球重力场模型的阶误差RMS为10-21量级,可以忽略不计;为了获取厘米级的大地水准面,在解算过程中应该将扰动位期望为零时对应的估值作为能量常数初始估计值,将其残差作为未知数一并求解,且能量常数误差应优于0.1 m2s2。  相似文献   

海岸带、海岛(礁)数字航空摄影方案优化策略     

王鑫  姜挺  张宝印  王连备 《测绘学院学报》2011,(3)

针对数字航空摄影作业技术流程中的作业标准、精度要求以及各关键指标的控制等问题,从数字航空摄影的技术计划制定、航线规划和各项技术指标的确定等方面入手,对基于海岸带、海岛(礁)特征的航摄分区、航线敷设、地面分辨率的确定、航摄季节与时间选择以及POS辅助航空摄影方案选择等内容进行了研究,为获取满足海洋测绘指标要求的航空摄影数据源提供支持。  相似文献