大型钢结构变形测试方法的研究与实践

介绍了精密全站仪进行结构测试的原理和方法,通过对某大型游泳跳水馆钢结构网架在张拉和加载试验中的变形测量实践,证明其具有作业简便、能够全面反映结构变形情况之优点,且精度较高,成果可靠。     

A multidirectional semi‐analytical method for analysis of laterally loaded pile groups in multi‐layered elastic strata

A semi‐analytical method for calculating the response of single piles and pile groups subjected to lateral loading is developed in this paper. Displacements anywhere in the soil domain are tied to the displacements of the piles through decay functions. The principle of virtual work and the calculus of variations are used to derive the governing differential equations that describe the response of the piles and soil. The eigenvalue method and the finite difference technique are used to solve the system of coupled differential equations for the piles and soil, respectively. The proposed method takes into account the soil surface displacement along and perpendicular to the loading direction and produces displacement fields that are very close to those produced by the finite element method but at lower computational effort. Compared with the previous method that considered only the soil displacement along the loading direction, accounting for the multi‐directional soil displacement field produces responses for the piles and soil that are closer to those approximated by the finite element method. Copyright © 2016 John Wiley & Sons, Ltd.     

Modification of strain wedge method for lateral soil-pile interaction in sandEI北大核心CSCD

A modified strain wedge (SW) method for analyzing the behavior of laterally loaded single piles in sand is proposed. The modified model assumes that the lateral displacements of a pile behind the three-dimensional passive soil wedge are nonlinear, which makes the horizontal soil strain variable with depths instead of a constant value in the original strain wedge model, and also employs two different hyperbolic models, one for describing horizontal stress increment-strain behavior of soil in the wedge, and the other for describing the shear stress-displacement property at the interface between soil and pile shafts. An example is analyzed to demonstrate the effectiveness of the modified method, and a good agreement is obtained. Finally, the effects of modifications on the lateral bearing capacity of pile shafts are discussed. The results show that the problem of overestimating the lateral bearing capacity of piles with strain wedge method can be ameliorated by introducing the assumption of nonlinear lateral displacements of piles. It makes the SW method more convenient and effective in analyzing the behavior of laterally loaded piles by introducing the new relationships of horizontal stress increment-strain and shear stress-displacement.     

深海系泊法向承力锚模型实验系统

法向承力锚是一种新型的拖曳嵌入式系泊基础.这种锚的工程应用仅有10 a时间.国内在此项技术上尚属空白.通过实验系统的设计,介绍了针对这种新型拖曳锚展开模型实验研究的实验平台.利用一些新型传感器和巧妙的机件设计,不仅实现了实验量测方法的创新,而且达到了经济实用的目的.实验结果也验证了整个系统设计的可靠性.     

P507负载泡塑反相色层富集岩石中的稀土元素

研究了Ｐ５０７负载泡塑萃取柱色谱分离富集稀土元素的条件，并与Ｐ５０７萃淋树脂柱进行了对比；拟定了Ｐ５０７负载泡塑反相色属富集岩石中稀土元素的方法。在ｐＨ２．５介质中ＲＥＥ上柱率９８％，用５０ｍｌ２．５ｍｏｌ／ＬＨＮＯ３作洗脱液，ＲＥＥ总回收率达９６．１％，干扰测定的Ｔｈ，Ｕ，Ｔｉ，Ｚｒ，Ｈｆ等均被除法。方法用于标样分析验证，结果与推荐值相符。     

滑坡治理方法及其应用实例

对目前国内外滑坡治理方法进行总结综述，例举了滑坡治理的几个实例，指出了滑坡治理的优先考虑方法。     

用载炭泡塑吸附原子吸收法测定地质样品中金

为达到简便、快速、准确测Au的目的，以泡塑为载体负载一定量的活性炭制成载炭泡塑，研究标准回收、酸度、流速及干扰试验结果，制定用载炭泡塑吸附，火焰原子吸收法测定地质样品中Au的实验方法，对部级含Au标样进行精度分析，并将测定外检样品的结果与活性炭富集及泡塑吸附法的测定结果做对照，表明该法具有较好的精密度和准确度，检出限为0.1ug/g，适合地质样品中Au的测定。     

横向受荷桩的最轻重量设计

尝试建立变截面桩的挠曲线微分方程，继而提出了变截面优化桩的概念，并给出了端承桩的一种优化算法。还以圆截面大孔径挖孔灌注桩为例，在桩顶受竖向荷载、水平横向力及弯矩作用时，进行了最轻重量设计。通过计算表明，使用变截面优化桩可使桩的体积减少３０％以上。     

斜坡地基刚性桩水平承载力上限分析

为探讨斜坡地基刚性桩水平极限承载力的计算方法，介绍柔性桩的等效刚性桩有效嵌入深度并引入极限水平地基反力分布形式。根据荷载指向坡外及坡内两种情况，提出适用于斜坡地基桩前土体的两种极限破坏模式。然后，基于极限分析上限定理，推导出两种荷载方向下的刚性桩极限承载力，并引入多组现场试验，验证了理论方法的合理性。探讨了边坡坡角、内摩擦角、黏聚力及荷载方向对极限承载力的影响，得出了一些规律性结论，并基于以上分析结果，提出斜坡地基刚性桩水平极限承载力随坡角变化的拟合公式。这些分析为斜坡地基上基桩设计提供了一定的参考，具有理论及工程应用价值。     

P–Y Curves for Piles Under Seismic Lateral Loads

This paper describes an experimentally based procedure for building dynamic P–Y curves for clays from the Campeche sound in the Gulf of Mexico and for Mexico City clays. Cyclic triaxial and resonant column tests were used to derive hyperbolic stiffness–strain and damping–strain functions that depend on soil plasticity and on relative consistency. The dynamic P–Y curves incorporate these functions and also include hysteretical and geometrical damping characteristics of the pile–soil system; they can be used directly in dynamic interaction analyses of structure–pile–soil systems in the time or the frequency domains. Usual practice relies on pseudo static formulations and a simplified alternative to include P–Y curves in this kind of analysis is also proposed, which is essentially the same as the dynamic ones but does not include radiation or hysteretical damping.