基坑工程开挖支护的数值计算分析

在详细分析地质条件及支护设计的基础上,运用ABAQUS软件,建立非对称分布土层的计算模型,采用Mohr-Coulomb弹塑性本构模型,对基坑开挖支护过程中土体变形和支护应力进行数值仿真。结果表明,基坑四周土体变形和围护结构内力均随开挖深度的增加而增大,当基坑两侧土层呈非对称分布时,基坑开挖过程中土层较薄一侧的土体将向远离基坑方向变形,施工过程中及时设置支护结构能有效地减少土体变形及上部支撑的内力。     

耙吸挖泥船集成平台管理系统的研究

本文以耙吸挖泥船为应用背景,介绍了挖泥船对主推进、电站、辅助机械、挖泥机械、仪表和操纵等构成的集成平台管理系统进行集中网络控制的实现方法,重点讨论了CANBUS、LONWORKS现场总线和工业以太网网络接口技术的解决方案。通过现场总线和工业以太网的有机结合,充分发挥二种网络的特点,较好地解决了耙吸挖泥船对多个子系统的集中控制和管理。应用表明由现场总线和工业以太网构成的二层网络平台,是解决挖泥船集中控制和管理的有效方法。     

浅谈公路软土地基处理

公路是线形带状的特殊人工建筑物,不可避免地经过不同的地质地区,也必然会遇到软土地质地区,若基底承载力不能满足设计要求,就需要进行软基处理。本文引用了10余篇文献,系统概括了软土地基处理方案,并总结了各种具体方法的适用条件,对出现的新方法、新工艺作了简单介绍。     

考虑土体渗透性径向变化的砂井地基数值模拟分析

土体渗透性是影响砂井地基固结的重要因素。为研究复杂条件下砂井地基的固结性状,通过编制用户子程序在ABAQUS中建立了渗透系数沿径向变化的砂井地基固结计算数值模型,对固结过程中的孔压分布及固结性状进行了研究。结果表明:渗透系数在径向上的变化情况会对砂井固结性状产生很大的影响。假定涂抹区渗透系数为常数时固结速率最慢;假定涂抹区渗透系数呈抛物线变化时固结速率最快;而假定涂抹区渗透系数呈线性变化时固结速率介于以上两种情况之间。此外,砂井地基的固结性状还受排水条件和土层特性等因素的影响。     

Support condition monitoring of monopile-supported offshore wind turbines in layered soil based on model updating

Monopile-supported offshore wind turbines (OWTs) are dynamically sensitive structures whose fundamental frequencies may be close to those of environmental and turbine-related excitations. The changes in fundamental frequencies caused by pile-soil interaction (PSI) may result in unwanted resonance and serious O&M (Operation and Maintenance) issues, which have been identified as major challenges in the research field. Therefore, a novel model updating framework with an implicit objective function is proposed to monitor both the stiffness and damping variation of the OWT system based on the measured vibration characteristics, which is further verified by laboratory tests. In particular, layered soil was considered in the tests to simulate the practical soil conditions of Chinese seas. Different pile lengths were introduced to consider the long-term PSI effects for rigid piles and slender piles. The results showed that the variation in the fundamental frequency is significantly reduced in layered soil compared with the pure sand scenario. For the OWT systems in layered soil, the variation in foundation stiffness is negatively related to the burial depth under cyclic loading. The proposed model updating framework is proven reliable for support condition monitoring of OWT systems in complicated soil conditions.