湿陷性坝基强夯法处理效果分析与评价

Effect analysis and evaluation of collapsible loess dam foundation reinforced by dynamic compaction

为客观评价强夯法处理湿陷性坝基的真实效果,结合杜窑沟水库湿陷性坝基的工程处理实例,对强夯后初检和终检的湿陷系数、干密度和孔隙比检测值与强夯前的检测值进行了对比分析。结果表明,强夯能够消除坝基湿陷性,提高土体干密度,减小孔隙比;验证了强夯后应延迟检测,待干密度和孔隙比逐步恢复提高的结论;强夯不能对特定深度的土体产生最优的压实效果,夯后干密度没有呈现分层特征。实例表明,8 000kN·m夯击能可以消除Ⅱ级非自重~Ⅲ级(严重)自重湿陷性壤土的湿陷性。同时指出需要通过更多的工程实践,进一步研究强夯的作用机理和内在规律,并探讨强夯质量检验的最佳时间。

To objectively evaluate the dynamic compaction treatment effects of collapsible loess dam foundation, the collapsible coefficient in initial test and final test, the dry density and porosity ratio Were compared with those before the treatment aiming at Duyaogou Reservoir, Ningxia. The results show that the dynamic compaction can reduce the collapsibility of dam foundation, in- crease soil dry density and reduce porosity ratio. It is verified that the quality test should not be conducted until the dry density and porosity ratio recover and increase; the dynamic compaction can not maximally strengthen the layer at a given depth and after the compaction the dry density has no stratification characteristic. The practice shows that the compaction energy of 8000 kN ·m can effectively reduce the collapsibility of grade lI of non - self - weight and grade llI of self - weight collapsible loess. The func- tion mechanism and laws of dynamic compaction as well as the optimized quality test time need to further study by more engineer- ing practices.