不同桩型情况下的桩基差异沉降三维有限元分析

近年来，以控制差异沉降为目标的桩基础变刚度调平方法在我国岩土工程界正受到越来越多的重视和应用。该文用三维有限元方法研究在同一基础下采用不同桩型情况时各桩沉降和刚度的关系，探讨通过改变桩型来调整刚度，最后控制差异沉降的方法，并通过一个工程实例阐述运用不同桩型进行设计的概念和方法，达到减小差异沉降。     

盾构施工地面长期沉降的神经网络预测

基于逆传播人工神经网络方法，建立了盾构施工地面长期沉降的非线性预测模型，建立了沉降与诸多影响因素：所处位置、时间、上覆土性参数及盾构施工参数等的关系模型。通过在上海地铁2号线龙东路一中央公园站区间资料的验证，发现与实际比较吻合。     

隧道施工引起横向地层沉降的随机预测

运用随机介质理论推导的横向地层沉降理论公式计算隧道施工引起的横向地层沉降时 ,影响范围角 β和隧道收敛值ΔR比较难以确定。详细分析了这两个参数的确定问题 ,并通过工程实例验证了横向地层沉降理论公式。     

Applicability of the rectangular hyperbolic method to settlement predictions of sabkha soils

In this paper, the applicability of the hyperbolic method to predict settlements of sabkha formations was investigated. Conventional and long-term consolidation tests were conducted, and the fit of the experimental data to a rectangular hyperbolic relationship was examined. The validity of the hyperbolic form as a representation of the settlement-time response of sabkha soils was further ascertained by analysing settlement records measured under an instrumented test embankment. The laboratory results indicated that the settlement-time behaviour could reasonably be represented by the hyperbolic relationship. Settlement estimates determined as the inverse of the slope of the initial linear segment multiplied by the slope of the theoretical curve, or obtained based on the radial slopes corresponding to 50% and 90% consolidation points, all underestimated the observed total settlements. However, the inverse of the slope of the final linear segment of the hyperbolic curve gave excellent estimates of the observed total settlements. The agreements between the predicted and observed in situ ultimate primary consolidation settlements are considered reasonable. Finally, except when the hyperbolic plot follows a straight line, the use of the hyperbolic method for prediction of total settlements of sabkha soils with prominent secondary compression behaviour has been shown to be both uncertain and impractical.     

青藏铁路冻土路基沉降变形现场试验研究

Based on the field data of ground temperature and roadway settlement observed during the construction of the experimental embankments over permafrost along the Qinghai-Tibetan Railway, this paper discusses the differences of frost process on the roadway surface from that on the natural ground surface, the changes of permafrost table under the roadway embankment, and the peculiarities of roadway settlement. Analyses of the test results show : 1) The differences of the freezing indexes between the roadway surfaces and the natural ground surfaces are less than those of the thawing indexes for all the test sections; 2) Since the measures of permafrost protection were taken, the permafrost tables under the embankments have raised after the roadway was constructed. The minimum is about 0.4 m and the maximum is 1.2 m; 3) the settlements of the roadway are mainly from the compression and creep of the icerich frozen soils under the original permafrost tables and the maximum has reached 6 ～ 8 cm during the first year after the embankments were constructed. Moreover, concerning the processes of roadway settlement, the deformation of the embankments has no obvious trend of attenuation at present. Especially,for the roadway with high embankments, the settlement may reach a remarkable value and much consideration must be given for this problem.     

城市快速道路软基处理方案探讨

介绍了深厚软土地基地质条件及处理技术要求,进行了软基处理的技术经济对比并选择了相应方案。此外,对选择的方案进行了参数设计及沉降分析预测。该方案实施后,取得了明显的经济效益。     

Shoreline development and Swedish colonisation of north-west Estonia during the Middle Ages

This paper focuses on how landscape development in areas of land uplift has come to direct the primary human colonisation on the coastal areas in north-western Estonia. A Swedish-speaking minority population has at least since medieval times settled these areas. On the basis of an estimation of the rate of land uplift, the shoreline development and topography of a section of the coast was reconstructed. In this respect, it appears that large changes have occurred in that during the Middle Ages, the coast was much steeper but also much longer than today, full of little bays and points. This means that the drainage of near-shore areas was more intensive and that it was possible to find suitable landing places and well-sheltered harbours in some locations. These locations appear to have been primary settlements of the Swedish-speaking colonists and are very similar to coastal settlements of the same age along other coasts of the central Baltic Sea basin. Thus, the results presented in the paper allow the selection of primary research sites for field studies of the early settlement history of this ancient Estonian minority. This revised version was published online in July 2006 with corrections to the Cover Date.     

环境因素对路基沉降影响的分析

在秦沈线的路基沉降观测过程中，发现在上部填土荷载恒定不变的情况下，不同区段、路基的不同平面位置上测得的沉降过程曲线，有的发生陡降，有的发生较大沉降后产生回弹，在详细分析了沉降过程曲线、地下水位变化曲线等资料的基础上，发现上述异常现象是抽取地下水和冻融作用这两个环境因素所致，抽取地下水会引起沉降猛增，而冻融作用使沉降发生往复变化，本文较为详细地阐述了这两个环境因素影响沉降过程的方式，并且就抽取地下水对沉降的影响作了一些量化的分析。     

深层搅拌桩复合地基沉降计算理论研究

为了寻找深层搅拌桩复合地基沉降计算的简便方法，根据已有的研究成果，进行了桩与桩周土间摩擦力分布规律的假设和简化，运用单位元法推导了深层搅拌桩复合地基沉降计算公式和设计用曲线，同时采用轴对称有限元法，对一实际工程的实测成果进行了分析。计算结果表明：文中理论计算的中级荷载下的沉降量值介于分层总和法与有限元法计算值之间，但文中方法比有限元计算法简单，比分层总和法更合理。