连续模拟降雨下岩溶区含砾石堆积体坡面径流产沙特征

为明确砾石含量对岩溶区石灰土质堆积体坡面径流产沙特征的影响,以土质坡面为对照,采用室内模拟降雨试验方法,研究了递增型降雨(0.5,1.0,2.0,2.5,3.0 mm/min)条件下偏土质(砾石含量30%)和偏石质(砾石含量70%)石灰土坡面的径流特性及侵蚀特征。结果表明:(1)随雨强增大,各坡面径流率呈稳定增长—波动的变化趋势,且土质坡面径流率整体小于2种含砾石坡面;偏土质、偏石质坡面累计产流量较土质坡面增加了0.49,0.37倍;(2)1.0~3.0 mm/min雨强下,土质坡面侵蚀速率在0.16~5.4 g/(m^2·s)范围内波动,整体呈稳定—波动增加的变化趋势;偏土质和偏石质坡面分别为0.16~5.4,0.06~0.74 g/(m^2·s),前者侵蚀速率变化范围大且波动剧烈,后者变化范围小且稳定;随砾石含量的增加,各坡面累计侵蚀量呈先增后减的变化趋势,偏土质坡面侵蚀量较土质坡面增加2.5倍,偏石质坡面较其减少了0.9倍;(3)土质、偏土质和偏石质坡面的侵蚀速率与径流率分别呈极显著正相关幂函数、线性函数和线性函数关系。研究结果可为桂西北岩溶区弃渣场水土流失治理提供一定的科学依据。     

Test about the Influence of Curing Age on the Engineering Properties of Lime-soil

Lime-soil has been widely used in communication and construction engineering as a cheap building material. But in practice, there is a little knowledge about the properties and monitoring of lime-soil. In this paper, through laboratory experiments, the influence of curing age and lime-soil ratio on the properties, such as shear strength and compressibility, is studied. Results show that the engineering properties of lime-soil are ameliorated with curing age. It is especially notable within 30 days and the engineering properties are better when the lime-soil ratio is greater than 2.5:7.5. Finally, the micro-mechanism of strength development is analyzed. Test results are useful for monitoring and controlling the quality of lime-soil construction. A proposal is suggested that for the standard, one-month strength should be taken for designing and monitoring the lime-soil.     

Study on Critical Length of Single Pile in Lime-Soil Pile Composite Foundation

The critical length of single pile in lime-soil pile composite foundation is studied by means of FEM. At the same time, the influencing factors such as lime-soil rate, diameter of pile and means of construction are studied.     

引水暗渠灰土挤密桩复合地基承载力可靠性分析

基于ANSYS概率设计系统(PDS),首次在引水暗渠灰土挤密桩复合地基承载力可靠性分析中运用非线性随机有限元法.以灰土挤密桩竖向荷载、弹性模量、泊松比及岩土的黏聚力等作为随机变量,并考虑了随机变量之间的相互作用,采用蒙特卡罗数值模拟法中的拉丁超立方进行抽样,计算出引洮工程引水暗渠湿陷性黄土灰土挤密桩复合地基以灰土挤密桩桩端最大应力为控制条件的失效概率为7.37%,可靠性指标为1.44.对随机变量进行了敏感度和相关性分析,判断出对失效概率影响较大的参数为土体的泊松比,其次为土体黏聚力、桩体弹性模量及土体弹性模量,其中,土体泊松比、土体黏聚力及土体弹性模量与灰土挤密桩结构最大轴向应力呈负相关,且相关性依次降低,桩体弹性模量与灰土挤密桩结构最大轴向应力呈正相关.研究结果可为工程施工、设计提供参考和依据.