不同掺砾量对黏土心墙的影响

为考察西南地区某黏土心墙坝在不同心墙掺砾水平下心墙的工作性态与安全情况,进而确定心墙坝掺砾施工方案,采用三维有限元方法,在不同的掺砾量水平之下,充分考虑掺砾量的增加对心墙渗透性与变形强度的影响,采用双线法计算各掺砾方案下的湿化变形,研究了大坝完建期及蓄水运行时心墙水平与竖向位移的变化规律,同时采用拱效应系数分析心墙拱效应的变化情况。研究结果表明:当掺砾量控制在50%以下时,伴随掺砾量增加,心墙的沉降变形减少,顺河流向变形减少,使心墙拱效应得到改善;当掺砾量大于50%时,掺砾对心墙的沉降变形与拱效应的抑制作用减弱,同时心墙顺河流向变形量增加。鉴于对于黏土心墙工作性态的综合考虑,建议相应工程中心墙料掺砾量宜小于50%。

Influences from different gravel contents on clay core-wall

In order to investigate the working behavior and safety status of the core-wall under the conditions of the various gravel content levels for a dam with clay core-wall in the Southwest China and then determine the gravel mixing construction scheme for it，3 － D finite element method is adopted to fully consider the influence from the increase of gravel content on the permeability and deformation strength of the core-wall，while the variation laws of both the horizontal and vertical displacements of the corewall during the completion period and the impoundment operation of the dam are studied through calculating all the gravel mixing schemes with double-line method，simultaneously，the variation of the arching effect of the core-wall is analyzed with the arching effect coefficient. The study result shows that when the gravel content is controlled to be below 50% ，both the settlement deformation and the deformation along the river flow direction of the core-wall are decreased along with the increase of the gravel content，thus the arching effect of the core-wall is improved. When the gravel content is larger than 50% ，the restraining effects from the mixed gravel on the settlement deformation and the arching effect of the core-wallare weakened，meanwhile，the deformation of the core-wall along the river flow direction increases. Under the comprehensive consideration of the working behavior of the clay core-wall，the gravel content of less than 50% is suggested for the relevant project.