坝前淤积土分段线性排水板-堆载预压耦合固结模型的研究  

Coupling Consolidation Model of Sectional Linear Drainage Plate and Surcharge Preloading of Upstream Sedimentation Soil of Dam

作　　者：姚自凯 YAO Zikai(Ningxia Water Resources and Hydropower Survey Design and Reserarch Institute Co.Ltd.,Yinchuan 750021,China)

机构地区：[1]宁夏水利水电勘测设计研究院有限公司,宁夏银川750021

出　　处：《宁夏工程技术》2020年第2期127-133,139,共8页Ningxia Engineering Technology

摘　　要：以宁夏南部黄土丘陵山区雅石沟水库除险加固工程为例,引入CS2(Consolidation Settlement 2)方法,基于有效应力、渗透系数与孔隙比之间的基本关系,建立坝前淤积土分段线性排水板-堆载预压耦合固结模型,编制了Fortran计算程序,以径向固结模型模拟计算了坝前淤积土中插入塑料排水板后,淤积土在加载过程中的固结度、超孔隙水压力的耗散状况和孔隙比的变化。结果表明:在计算模型中增设竖向排水板,淤积土的固结速率明显加快,在第47 d时固结度即达到87.32%,与未增设竖向排水板时计算的淤积土固结度(88.76%)相比,提前43 d达到相近的固结度;由于竖向排水板的布设,淤积土中超静孔压随着时间的增加逐渐消散,与未布设排水板时淤积土内超静孔压值在第90 d时为51.88 kPa相比,布设排水板后在第47 d时,坝前淤积土层超静孔压沿深度的分布值最大为5.67 kPa;坝前淤积土分段线性排水板-堆载预压耦合固结模型与相关文献中有限元软件模拟所得结果基本上是一致的,验证了模型的准确性,该模型能够较好地模拟淤积土中增设竖向排水板的排水固结过程,用于预测淤积土的固结沉降。Based on the basic relationship between effective stress,permeability coefficient and void ratio,CS2 method is introduced to establish the coupling consolidation model of sectional linear drainage plate and surcharge preloading for the silted soil in front of the dam,and Fortran program is developed to simulate and calculate the effect of plastic drainage plate inserted into the silted soil in front of the dam.The degree of consolidation,the dissipation of excess pore water pressure and the change of void ratio in the process of loading are investigated.The results show that the consolidation rate of the silted soil is obviously accelerated by adding the vertical drainage plate in the calculation model,and the consolidation degree reaches 87.32%on the 47th day.Compared with the consolidation degree of the silted soil calculated without adding the vertical drainage plate(88.76%),it reaches the same consolidation degree 43 days in advance.Due to the arrangement of the vertical drainage plate,the excess pore pressure in the silted soil gradually dissipates with the increase of time.Compared with 51.88 kPa at 90 days when the drainage plate is not installed,the distribution value of the excess pore pressure along the depth of the silted soil layer in front of the dam is 5.67 kPa at 47 days when the drainage plate is installed.The model of the coupling of the sectional linear drainage plate and the preloading consolidation of the silted soil in front of the dam is basically consistent with the results of the simulation by finite element software in the relevant literature,which verifies the value of the model.The accuracy of this method can be used to simulate the consolidation process of adding vertical drainage board in the silted soil and predict the consolidation settlement of the silted soil.

关 键 词：坝前淤积土 分段线性差分模型 排水板 堆载预压 

分 类 号：TV223[水利工程—水工结构工程]