中文摘要：

衬砌与围岩是水工隧洞的主要组成部分,外水压力是其承担的主要荷载之一.结合某水电站工程实例,建立其发电引水隧洞的有限元数值分析模型,针对衬砌与围岩有条件联合承载作用特征,对衬砌外围岩变形模量进行折减以反映围岩的作用,并引入具有一定抗拉强度的薄层单元量化反映衬砌与围岩有条件联合承载能力.结果表明：与衬砌完全单独承载外水压力计算结果相比,围岩在承担外水压力中的作用不容忽视,且随着外围岩体变形模量的增加,其所分担的外水压力越大;采用薄层单元量化后,衬砌与围岩的联合承载机理更为明确,薄层单元开裂前,围岩承担外水压力较多,薄层单元开裂后,衬砌承担外水压力较多,因而要确保回填灌浆和固结灌浆质量,以提高衬砌与围岩联合承载能力.

英文摘要：

External water pressure is one of the main loads acting on hydraulic tunnel,which consists of lining and surrounding rock.A numerical model of a hydropower diversion tunnel is built according to the combined load bearing mechanism of lining and surrounding rock.The deformation modulus of the surrounding rock near to lining is reduced to indicate the influence of surrounding rock.A thin-layer element which has a certain tensile strength is also developed to quantify the limited cooperation between lining and surrounding rock.The results show that the surrounding rock takes an important role.As the deformation modulus of the surrounding rock increasing,the rock bears more external water pressure.And the combined load bearing mechanism is clearer than before when the tensile strength is fixed.The surrounding rock bears more external water pressure before the thin-layer element cracked.The lining bears more pressure after the element cracked.In order to enhance the surrounding rock’s combined load bearing capacity,it’s important to ensure the quality of backfill grouting and consolidation grouting.