碎石桩加固地基对风化料坝应力变形影响研究

Influence of vibrofloatation gravel pile reinforced foundation on stress and deformation of a weathered dam

近年来振冲碎石桩逐渐应用到土石坝坝基处理中,为研究碎石桩加固地基对大坝应力变形的影响,以覆盖层地基上的某混凝土防渗墙风化料坝为背景,利用碎石桩对地基进行加固处理。在考虑坝料流变特性的基础上,采用非线性有限元方法,计算分析在碎石桩加固地基与未加固地基下,大坝在蓄水期和运行期的应力变形。通过对比计算结果,系统总结了碎石桩加固地基对坝体与防渗墙应力变形的影响规律。结果表明:在碎石桩加固地基下,大坝在蓄水期、正常运行1 a、正常运行5 a、正常运行10 a后,坝体和防渗墙的应力和变形相比未加固地基下都有所减小,相对而言,变形减小的幅度更大一些。可见利用碎石桩加固地基,可以有效地改善坝体和防渗墙的应力和变形,利于大坝保持稳定运行状态。

Vibroflotation gravel piles have been gradually applied to the treatment of earth-rock dam foundation in recent years.In order to study the influence of the foundation reinforced by gravel piles on the stress and deformation of the dam,a weathered concrete diaphragm wall dam on the alluvium deposit foundation was used as the study subject,and its foundation was reinforced by vibroflotation gravel piles.By considering the rheological characteristics of the dam material,we used the nonlinear finite element method to calculate and analyze the stress deformation of the dam during the water storage period and the running period with the reinforced foundation of vobroflotation gravel piles and the unreinforced foundation.By comparing the results of the analysis,we summanized the influence of the vibroflotation gravel pile reinforcement on the stress and deformation of the dam body and the diaphragm wall.The results showed that with the reinforcement of gravel piles,after the normal operation of 1 year,5 years,and 10 years,the stress and deformation of the dam body and diaphragm wall on reinforced foundation were smaller than those on unreinforced foundation during water storage period,and the reduction of deformation of the reinforced foundation was relatively larger in magnitude.It can be seen that the reinforcement of gravel piles can effectively improve the stress and deformation of the dam body and the diaphragm wall,which is conducive to maintaining stable operation of the dam.