软土地层基坑施工过程土锚索受力状态原位试验研究

针对软土地层深基坑施工扰动引发锚索支护系统预应力损失及其支护效果风险演化等不确定性问题,结合温州机场大型深基坑工程,进行基坑开挖全过程土锚索预应力分布特性及其演化的原位试验。通过实时数据,系统研究基坑开挖过程锚固力变化特性、施工方式和参数对锚固力的影响规律、锚索几何参数对自身受力和作用效果的影响。结果表明,近距离土体开挖卸载对锚索体系的实时锚固力产生较大幅度的突变性影响;随基坑开挖过程,各试样锚固力呈缓慢增大趋势;锚固力的损失与增大,取决于锚索结构的几何参数,当锚索长度大于等于3倍基坑深度时,锚固力损失趋于零并呈现逐渐增加趋势。该结果对软土基坑锚索支护设计具有借鉴意义。     

施工及环境因素诱发污水处理池差异沉降及渗漏风险

针对地基变形特征及其引发的大型污水处理池混凝土结构破裂渗漏风险，研究人工降水、开挖与桩基加固、滨海潮汐地下水渗透等条件下的地基变形特性，并建立地基变形基本方程及多因素综合影响下的统一函数表达式。结合上海白龙港污水处理厂工程，分析了工程区域施工及环境因素可能产生的地基变形及其对结构受力的不良影响。结果表明：i）地基变形曲率对结构受力产生直接影响，曲率半径越小，结构的附加应力越大、致裂风险越高；ii）结构高度越大，对地基弯曲变形的反应越敏感；iii）结构抗弯刚度突变处，应力集中程度高、局部应力超限风险增大。     

Equivalent continuum model of rock mass with arbitrary fractures

The constitutive model and equivalent deformation modulus of an arbitrary column in representative elementary volume (REV) of fractured rock mass are derived. The deformation of fractured rock mass is composed of the rock part and the fracture part. The elasto-visco-plastic property is considered in this model. For the convenience in engineering practice, the complex elasto-visco-plastic model and its equivalent modulus are degraded, and the rock is taken as an elastic body. By statistical analysis of the geometric positions of the column and the fracture, the equivalent modulus of rock mass with arbitrary fractures is obtained.