Influence of water saturation on propagation of elastic waves in transversely isotropic nearly saturated soil

Biot's two-phase theory for fluid-saturated porous media was applied in a study carried out to investigate the influence of water saturation on propagation of elastic wave in transversely isotropic nearly saturated soil. The characteristic equations for wave propagation were derived and solved analytically. The results showed that there are four waves: the first and second quasi-longitudinal waves (QP1 and QP2), the quasi-transverse wave (QSV) and the anti-plane transverse wave (SH). Numerical results are given to illustrate the influence of saturation on the velocity, dispersion and attenuation of the four body waves. Some typical numerical results are discussed and plotted. The results can be meaningful for soil dynamics and earthquake engineering.     

3D analytical solution for a rotating transversely isotropic annular plate of functionally graded materials

The analytical solution for an annular plate rotating at a constant angular velocity is derived by means of direct displacement method from the elasticity equations for axisymmetric problems of functionally graded transversely isotropic media. The displacement components are assumed as a linear combination of certain explicit functions of the radial coordinate, with seven undetermined coefficients being functions of the axial coordinate z. Seven equations governing these z-dependent functions are derived and solved by a progressive integrating scheme. The present solution can be degenerated into the solution of a rotating isotropic functionally graded annular plate. The solution also can be degenerated into that for transversely isotropic or isotropic homogeneous materials. Finally, a special case is considered and the effect of the material gradient index on the elastic field is illustrated numerically.     

Pure bending of simply supported circular plate of transversely isotropic functionally graded material

INTRODUCTION In recent years, functionally graded materials (FGMs) have attracted more and more attention. Due to their continuously varying material properties in space on the macroscopic scale, FGMs, therefore, are usually superior to conventional fiber-matrix materi-als in mechanical behavior, especially for perform-ance under thermal loading. Now FGMs have been widely used in various fields including electronics, chemistry, optics, biomedicine, etc. Heretofore, volumes of literatu…     

Development of the shear bands in saturated soil

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神经网络在预测饱和砂土液化中的应用

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　Ｍｏｄｅｌｉｎｇｏｆｓｏｉｌｂｅｈａｖｉｏｕｒｐｌａｙｓａｎｉｍｐｏｒｔａｎｔｒｏｌｅｉｎｄｅａｌｉｎｇｗｉｔｈｐｒｏｂｌｅｍｓｒｅｌａｔｅｄｔｏｓｏｉｌｍｅｃｈａｎｉｃｓａｎｄｆｏｕｎｄａｔｉｏｎｅｎｇｉｎｅｅｒｉｎｇ .Ｏｖｅｒｔｈｅｐａｓｔｆｏｕｒｄｅｃａｄｅｓ ,ｍａｎｙｒｅｓｅａｒｃｈｅｒｓｈａｖｅｄｅｖｏｔｅｄｅｎｏｒｍｏｕｓｅｆｆｏｒｔｓｔｏｆｏｒｅｃａｓｔｉｎｇｔｈｅｌｉｑｕｅｆａｃｔｉｏｎｏｆｓａｔｕｒａｔｅｄｓｏｉｌｕｎｄｅｒｖａｒｉｏｕｓａｓｓｕｍ…     

海积饱和软土地基处理优化设计分析

针对海积饱和软土地基处理实际工程中采用搅拌桩复合地基和堆载预压排水固结两种方法,进行技术与经济的优化设计分析,预测饱和软土固结度及其沉降特征。通过工程现场监测数据和实际应用效果进行对比,验证理论分析成果和固结度计算以及沉降预测的有效性,结果表明,堆载预压和排水系统的有效结合,对处理沿海饱和软土地基具有良好效果,且经济有效。     

土壤含水量对浑水入渗能力的影响

土壤含水量对浑水入渗能力产生明显影响,土壤含水量由小变大,浑水入渗能力减小;3个入渗参数随土壤含水量的增大而减小。研究结果对于指导浑水入渗及引洪补源具有重要意义。     

Iterative method on well bore boundary in numerical modeling of variably saturated flow

An iterative method was developed for incorporating the well bore boundary into the finite difference model of water flow in variably saturated porous media. Six cases were presented involving groundwater pumping or injection to demonstrate the advantages of the iterative method over the traditional method. For the iterative method, the total flux gradually approached the well discharge and the flux profile was non-uniform. And the iterative method took into account the variation of well bore water table. Compared to the traditional method, the iterative method can simulate the variably saturated flow caused by pumping or injection more realistically.     

论西部大开发中的水土保持

在分析了我国水土保持的现状及存在的问题和西部环境与西部大开发关系的基础上，从西部大开发的目标和任务出发，提出了西部水土保持综合治理措施。     

Influence of some agricultural practices on the soil acidification in acid precipitation areas

1 Introduction Soil acidification is one of the major course of soil degeneration, which leads to decrease in the pH value, loss of base and nutrient content by leaching, aluminum and heavy metal activation, consequently results in deforestations and decr…     

益智仁水提取物对脑老化小鼠海马SOD活力及蛋白含量的影响

[目的]观察益智仁水提取物(A lp in ia oxyphylla M iq.fru it,AOF)对脑老化小鼠海马SOD活力及海马蛋白含量的影响.[方法]选用健康成年昆明种小鼠60只,雌雄各半,随机数字表法将其分成5组:对照组、模型组、脑复康组、AOF低剂量组、AOF高剂量组.用D-半乳糖皮下注射诱导小鼠脑老化模型,采用学习记忆行为训练和生化测定结合的方法,观察AOF对小鼠学习记忆能力的影响,测定海马组织超氧化物歧化酶(SOD)和海马蛋白含量.[结果]①AOF对脑老化小鼠学习记忆能力的影响:模型组达标所需训练次数显著高于对照组(p<0.01),AOF低、高剂量组达标所需训练次数显著低于模型组(p<0.01).②AOF对脑老化小鼠海马SOD活力的影响:模型组小鼠海马SOD活力显著低于对照组(p<0.05),AOF低、高剂量组小鼠海马SOD活力显著高于模型组(p<0.05).③AOF对脑老化小鼠海马蛋白含量的影响:与对照组比,模型组小鼠海马蛋白含量显著降低(p<0.01);与模型组相比,AOF低、高剂量组小鼠海马蛋白含量显著增高(p<0.01).[结论]AOF可提高脑老化小鼠海马SOD活力,增加海马蛋白含量,对D-半乳糖诱导脑老化小鼠的学习记忆障碍具有显著的改善作用.