中文摘要：

为了研究盾构输水隧洞设垫层预应力复合衬砌的受力特性，以南水北调中线穿黄隧洞工程为背景，采用有限元软件ANSYS建立了盾构输水隧洞预应力复合衬砌结构的整体三维有限元模型，对比了有垫层衬砌结构与无垫层衬砌结构的内衬、外衬的应力分布情况，分析了不设垫层与设不同刚度的垫层时内衬与外衬之间的传力机制，以及垫层刚度的变化对隧洞内衬预应力混凝土环向应力的影响。计算分析结果表明：预应力复合衬砌中设置合适的垫层可以充分发挥内衬预应力的作用效果，实现内衬、外衬独立承载的设计目的，从而可以改善内衬和外衬在隧洞充水运行时的应力分布状态并使外衬具有较大的压应力，提高了衬砌结构的整体安全性；同时，垫层刚度越小，内衬传递给外衬的水压力荷载比越小，越能充分发挥内衬的锚索预应力效果；这种设垫层预应力复合衬砌结构形式在软土地层条件下的高埋深、高内压盾构输水隧洞工程中具有应力分布状态好、防水性能好、整体结构安全度高等综合优势。

英文摘要：

The force characteristics of prestressed conveyance shield tunnel are studied. To simulate this composite linings with a cushion layer for water structure, a three-dimensional fmite-element model of whole structure is developed on a platform of the FEM code ANSYS and applied to the design of the Yellow River-crossing tunnel for the middle route project of south-to-north water diversion. For two cases of the composite structure with or without a cushion layer, stress distributions in the inner lining and outer lining are compared, and force transmission mechanism between the two linings are analyzed for different stiffness of the cushion. And the effect of a change in cushion stiffness on the hoop stress in the linings is examined. The results reveal that for the structure of prestressed composite linings, if a cushion layer is added appropriately, its prestressed tension can be in full use and the design objective for the inner or outer lining to work independently in load beating can be achieved. This improves the distributions of stress in the linings and makes the outer lining bear greater compressive stress, hence improving the overall safety of lining structure. And a decrease in cushion stiffness results in a lower ratio of water pressure transfer from the inner to outer lining and a better effect of prestressed tension in the inner lining. Thus, the composite structure with a cushion layer is superior in stress distribution, waterproof performance, and overall structural safety for a water conveyance shield tunnel of high internal pressure and great buried depth in soft soil foundation.