旱涝急转工况下土石坝上游粘土防渗体水力劈裂研究  

Study on Hydraulic Fracturing of Clay Anti-seepage Body in the Upstream of Earthrock Dam Under the Condition of Drought Flood Abrupt Alternation

作　　者：袁自立 叶伟[2,3] 徐章耀 杜玉娟 YUAN Zi-li;YE Wei;XU Zhang-yao;DU Yu-juan(Management Bureau of Baiguishan Reservoir in Henan,Pingdingshan 467031,China;Nanjing Hydraulic Research Institute,Nangjing 210029,China;Dam Safety Management Center of the Ministry of Water Resources,Nangjing 210029,China)

机构地区：[1]河南省白龟山水库管理局,河南平顶山467031 [2]南京水利科学研究院,江苏南京210029 [3]水利部大坝安全管理中心,江苏南京210029

出　　处：《水电能源科学》2024年第7期114-118,共5页Water Resources and Power

基　　金：国家自然科学基金黄河水科学研究联合基金项目(U2243244);中央级公益性科研院所基本科研业务费专项资金(Y721008)。

摘　　要：近年来作为极端小概率事件的旱涝急转工况频繁出现,极易造成防渗体缺陷扩展,诱发工程失事。通过在模型试验与数值计算分析的基础上探讨了旱涝急转工况下土石坝粘土防渗体中的水力劈裂问题。结果表明,旱涝急转工况中的干旱过程促使土体基质渗透性降低,同时导致防渗体产生裂缝,具备了发生水力劈裂的必要条件。理论分析推导了沿裂缝所在平面产生水力劈裂破坏的渗透压力理论值,离心试验模型测得铺盖层孔压骤降的同时砂层孔压骤增,表明裂缝受高水压作用产生劈裂贯穿了防渗体,裂缝处测量孔隙水压力值与理论推导结果基本一致。旱涝急转过程中裂缝处土体内的压应力先是逐渐增大,随后不断减小最终转变为拉应力,从而导致水力劈裂。研究结果对旱涝急转工况下的土石坝安全运行具有指导作用。The condition of drought-flood abrupt alternation,as an extremely rare event,frequently occurs,which can easily lead to the expansion of defects in the anti-seepage body and trigger engineering accidents.On the basis of model experiments and numerical calculation analysis,the hydraulic fracturing problem in the clay anti-seepage body of earth rock dams under the condition of drought-flood abrupt alternation was explored.The results indicate that the drought process reduces the permeability of soil matrix and leads to the formation of cracks in the anti-seepage body,providing a necessary condition for hydraulic fracturing to occur.Theoretical analysis has derived the theoretical value of seepage pressure for hydraulic fracturing failure along the plane where the crack is located.In the centrifugal test model,it was found that the pore pressure in the covering layer decreased sharply while the pore pressure in the sand layer increased sharply,indicating that the crack was subjected to high water pressure and split through the anti-seepage body.The measured pore water pressure value at the crack is basically consistent with the theoretical derivation results.The compressive stress inside the soil at the crack first gradually increases,then decreases continuously and finally transforms into tensile stress,leading to hydraulic fracturing.The research results have guiding significance for the safe operation of earth rock dams under the condition of drought-flood abrupt alternation.

关 键 词：旱涝急转 粘土铺盖 水力劈裂 离心试验 数值计算 

分 类 号：TV641[水利工程—水利水电工程]