赣粤闽交界及邻区近年中强地震加卸载响应比特征研究

以地震应变能作为响应因子,研究了1997至2007年赣粤闽交界及邻区4．0级（ML≥4．0）以上中强地震临震前的加卸载响应比（Y值）的基本变化特征,研究结果表明,80％以上的地震在临震前Y值呈现出高值异常形态。因而它可以作为此地区地震预测的一种手段。     

主应力轴旋转情况下土的各向异性研究进展

从理论和实验两个方面对国内外主应力轴旋转情况下土的各向异性研究进行了对比和总结,并提出了一些研究建议。指出:在理论方面,应对屈服面方程采用应力分量表示的模型在三维空间里进行屈服面性状的描述,并考虑不同加载方向下屈服面的变化特性以及旋转硬化的问题;而实验方面,则应多以粘性土为研究对象,结合理论进行对加载方向变化时土体屈服面变化特性的实验研究以及旋转硬化规律的实验验证。     

基于三角模糊数随机模拟的地下水环境系统综合风险评价模型

采用随机模拟方法模拟三角模糊数,把三角模糊数及函数间运算简化为普通的实数之间运算,建立基于三角模糊数随机模拟的地下水环境系统综合风险评价模型(ARA-SSTFN)。结果说明:以置信区间形式表示的ARA-SSTFN评价结果,比现有常规方法结果提供评价结果可靠性方面更多信息,能反映受多种不确定性因素综合影响的地下水环境系统综合风险评价客观实际情况;ARA-SSTFN在流域水资源、水环境和水旱灾害等有随机性、模糊性和数据资料不精确等多种不确定性因素综合作用的各种资源环境系统综合风险评价问题中有推广应用价值。     

《返乡》与《归去来兮辞》的文化和地理环境特征影响分析

德国浪漫主义诗人荷尔德林与中国田园诗人陶渊明都被誉为“诗人中的诗人”,他们的诗中都蕴涵着深深的“故土”情结。研究他们的代表作——荷氏的《返乡》与陶氏的《归去来兮辞》,都有许多耐人寻味的地方。尽管文化背景、文化语境、情感基调不一,然而,他们构筑的对“诗意栖居”的憧憬和神往却折射出人类共同的生命艺术境界。本论文分别从两首诗的归因、归程、归宿三方面来论述,两种文化和不同地理环境的特质和基因塑造了两个不同时代、不同地域的诗人,形成了他们别具风格的诗境。     

Proposed nonlinear 3-D analytical method for piled raft foundations

The load distribution and deformation of piled raft foundations subjected to axial and lateral loads were investigated by a numerical analysis and field case studies. Special attention is given to the improved analytical method (YSPR) proposed by considering raft flexibility and soil nonlinearity. A load transfer approach using p–y, t–z and q–z curves is used for the analysis of piles. An analytical method of the soil–structure interaction is developed by taking into account the soil spring coupling effects based on the Filonenko-Borodich model. The proposed method has been verified by comparing the results with other numerical methods and field case studies on piled raft. Through comparative studies, it is found that the proposed method in the present study is in good agreement with general trend observed by field measurements and, thus, represents a significant improvement in the prediction of piled raft load sharing and settlement behavior.     

Reliability of shallow foundations designed against bearing failure using LRFD

Worldwide, there is growing interest in the development of a rational reliability-based geotechnical design code. The reasons for this interest are at least two-fold; first, geotechnical engineers face significantly more uncertainties than those faced in other fields of engineering, therefore there is a need to properly characterize and deal with these uncertainties. Second, for decades, structural engineers have used a reliability-based design code, and there is a need to develop the same for geotechnical engineers, in order that the two groups can ‘speak the same language’. This paper develops a theoretical model to predict the probability that a shallow foundation will exceed its supporting soil's bearing capacity. The footing is designed using characteristic soil properties (cohesion and friction angle) derived from a single sample, or ‘core’, taken in the vicinity of the footing, and used in a load and resistance factor design approach. The theory predicting failure probability is validated using a two-dimensional random finite element method analysis of a strip footing. Agreement between theory and simulation is found to be very good. Therefore, the theory can be used with confidence to perform risk assessments of foundation designs and develop resistance factors for use in code provisions.     

深层水泥土搅拦桩在软土地基处理中的应用

通过对深层水泥土搅拌桩的加固机理及复合地基承载力性状的简要分析,根据国家现行规范,结合具体地基处理工程实例,对深层水泥搅拌桩在软土地区地基加固处理中的方案选择、设计、施工及检测中的常见技术要点作初步探讨。     

Numerical analysis on post-grouted drilled shafts: A case study at the Brazo River Bridge,TX

This paper investigates the effects of post-grouting on the behavior of drilled shafts using a case study carried out at the Brazo River, Texas. Commercial finite element software, PLAXIS, was used to quantify the improvement of the tip resistance and side shear resistance of post-grouted drilled shafts (PGDS). The input material parameters of PLAXIS were initially estimated using CPT sounding results, and then the parameters were updated by calibrating the numerical results against full-scale STATNAMIC load test results. Based on the numerical analysis, the authors concluded that (1) the increase in total resistance of PGDS resulted from soil improvement at the shaft tip, (2) the apparent increase in side shear resistance resulted from side shear reversal that occurred during post-grouting, and (3) the apparent increase in the tip resistance of PGDS may be caused by stress relief of the grout. In addition, two approaches to estimate the resistance of PGDS were compared against numerical results. In this case study, the Axial Capacity Multiplier (ACM) approach over-predicted the total resistance whereas the Tip Capacity Multiplier (TCM) approach reasonably predicted the increase in total resistance.     

Impulsive force of debris flow on a curved dam

Although Sabo dams are an efficient method for river and basin management, traditional Sabo dams have a great impact on ecology and landscape. Moreover, such dams are hit and often damaged by great impulsive force when they block the debris flow. Therefore, alternative shapes for Sabo dam deserve thorough investigation. In this investigation, a curved dam was designed by changing the upstream-dam-surface geometric shape to reduce the impulsive force of the debris flow, with enhanced stability and reduced concrete mass being the anticipated outcomes. In this study, the flume and laboratory facilities simulated the impulsive force of the debris flow to the Sabo dams. Three geometric forms, including vertical, slanted and curved Sabo dams, were used to determine the impulsive force. Impulsive force theories of the debris flow were derived from the momentum equation and the Bernoulli equation. In these, the impulsive force was balanced by the friction force of the Sabo dam and the opposite force of the load cell behind the dam as it was hit by the debris flow. Positive correlations were found when comparing the experimental data with the theoretical results. These findings suggest that our impulsive force theory has predictive validity with regard to the experimental data. The results from both theory and experimental data clearly show that curved darns were sustained less force than the other darns under the same debris flow. This comparison demonstrates the importance of curved geometry for a well-designed Sabo dam.