土工格栅加固处理软土路基优化研究

运用MIDAS/GTS有限元软件并结合具体的工程背景,构建出待施工路基的三维模型,旨在有效模拟不同土工格栅加筋层数下,软土路基的稳定性变化情况,主要指标包括位移、应力、稳定性系数。分析结果显示:在加筋层数增加到3层时,缩小路基位移和应力效果最明显。

土工格栅地基加固效果的试验研究

现行加筋土结构设计规范中一般以筋材抗拉强度作为设计指标。实际上,影响地基加固效果的因素有多种,除拉伸强度外,还需关注格栅生产工艺、网孔形状、大小、肋条形状等物理性质和结构特点对加固效果的影响。通过原位浅层平板载荷试验,研究了四种不同类型土工格栅加固地基的承载力和变形性能。试验表明,土工格栅加固地基后其BCR值可提高至1.19~1.43,总沉降减少率至少达50%以上,但不同格栅加固效果并不与格栅强度成正比,更与格栅类型、网格尺寸和结构完整性等有关。地基加固效果依次为拉伸型三向格栅>拉伸型双向格栅>焊接型双向格栅>经编型双向格栅。三向格栅由于其特殊的三角形网孔构造和尺寸大小,与基土的相互作用效应更显著,承载力特征值可提高43%,沉降减少率达63%,沉降主要发生在上部砂垫层内,对深部土体的扰动更小。网格过小或过大、以及结点易剥离性都不利于充分发挥格栅的整体加固作用。因此在加筋土结构设计和筋材选型时,设计师不应简单地以抗拉强度作为设计唯一指标,应同时关注其物理结构特点和网格尺寸大小与填料粒径的适配性。

高土石坝抗震措施综述

针对国内建设的越来越高的土石坝,分析了地震时高土石坝的破坏性态,对高土石坝抗震措施研究方面的成果进行归纳阐述,对高土石坝抗震措施进行展望。

Effect of geogrid reinforcement on soft and medium dense soils

The field tests were carried out to examine the reinforcement effect of a geogrid on various conditions of embankment height,the number of passages of vibratory roller,the number of reinforced layer of geogrid,and soil properties.The test results of the dynamic earth pressure indicate that the soil reinforced by geogrid is very effective to increase the stiffness of soil,especially in soft soil.The dynamic earth pressure ratio,which is defined as the ratio of dynamic earth pressure to self weight of soils,exponentially decreases as the embankment height increases.The dynamic earth pressure ratio increases up to 80% for soft soils reinforced by both one layer of geogrid in place of no reinforced soils and two layers in place of a single layer of geogrid.