梯田式填筑-降雨时序作用下沟谷区高填方地基变形与边坡稳定性分析

山区城镇化建设力度逐步加大,削山填沟工程广泛分布,高填方地基沉降变形与边坡稳定性是安全建设重要的问题之一。基于典型沟谷区高填方梯田式填筑模型,结合流固耦合方法和极限平衡理论提出了梯田式填筑—降雨时序作用下沟谷区高填方地基变形与边坡稳定性分析方法,然后通过室内试验确定填筑体力学参数,分析梯田式填筑过程中高填方边坡内部响应规律,最后从多角度分析降雨时序作用下高填方地基变形与边坡稳定性时空演化规律,同时结合现场深部监测数据验证模拟结果的合理性,并将其运用到湖北省十堰市郧西县扶贫产业园项目。结果表明:填筑体随含石量增加,黏聚力总体呈波动式下降趋势,内摩擦角相对变化不大,饱和作用下试样抗剪强度具有显著弱化作用;填筑时步过程中,填筑层对边坡变形影响具有一定的时空限制范围;降雨时序作用下,填方区降雨影响深度为距地表12 m范围附近,结合现场长期监测数据,与模拟结果较为相似。研究成果能为削山填沟高填方边坡风险评估与地质灾害防治提供技术与实践经验。

Rock fragmentation under different installation polar angles of TBM disc cutters

The disc cutters of tunnel boring machine(TBM) are installed with different polar angles. This causes the cutting depth difference between adjacent disc cutters on the tunnel face. A rock-cutting model was established to study the rock fragmentation law between adjacent disc cutters with different polar angles based on particle flow code(PFC). The influence of polar angle of adjacent disc cutters on rock cracks and stresses under different cutter spacing and penetration was studied. Research shows that polar angle difference leads to the discontinuity of rock-fragmentation process by adjacent cutters. The effect of rock-fragmentation is influenced by the cutting depth difference between adjacent cutters. The effect of rock-fragmentation performed best, meanwhile large rock blocks were flaked when the difference of cutting depth is half of the penetration. Too large or small difference of the cutting depth will cause high specific energy consumption of rock fragmentation. The specific energy consumption is relatively small when the difference of cutting depth is half of the penetration.

医用辐射源防护监测中环保与卫生标准的差异分析

目的:通过与卫生标准对比,分析环保标准在医用辐射源监测方面的不足。方法:讨论环保标准与卫生标准的差异,并对环保标准中缺少的关键项目对监测结果的影响进行分析。结果:与卫生标准相比,环保标准在普放与放疗监测中漏掉许多关键参数的要求,造成监测工作存在漏洞,给行政部门执法带来不便。