Thermal Effect Simulation And Analysis Of Tunnel Lining During Construction With Object-Oriented Programming

Tunnel is a primary structure type in hydraulic engineering. The thermalstress during construction in tunnel lining has not been paid much attentionbefore. However, with the application of high strength concrete and massconcrete in tunnel linings, the thermal effect seriously influences the stabilityand durability of lining structures. Therefore, it is significant to study thethermal effect on tunnel lining structures during construction. Nowadays, there have been a lot of achievements in the field of FiniteElement Method (FEM), including the simulation and analysis of thermaleffect in structures during construction. Nevertheless, the analysis software(or program) is mostly implemented with procedural method. As the rapidexpansion of functions in FEM programs, the software crisis caused by thisprogram design method is more and more serious. The Object-OrientedProgramming method (OOP) can solve this problem efficiently. Due to theadvantages, such as easy to be maintained, re-useful, flexible and efficient,the OOP grows fast in FEM area. Thus, using OOP to develop or modify FEMsoftware is a future trend. In this thesis, according to the property of FEM, the simulation programis analyzed and designed with Object-Oriented technique. The objects andclasses are created with responding entities in FEM, such as Node Class,Element Class and Material Class. Furthermore, the program frame is designedsubjected to the relationship between objects and it is implemented with C++. With the software SPS_FET2D that is to simulate thermal effects duringconstruction, the transient temperature field and stress field in Xiaolangdidiversion tunnel lining is analyzed and according to this result, the mechanismand reason of crack is presented. To the real construction plan, several newmeans are presented, which include changing the dividing of concrete block, - II -optimizing mix proportion of concrete to decrease the hydration heat, curingthe lining surface with foam or other materials, changing the thickness oflining structure, and the result is reported. Based on the result of FEA, thetemperature control standard and crack prevention measures of Xiaolangdidiversion tunnel are proposed in this thesis. One treatment to hydration heat loads in the FEA of large time step ispresented to simulate the transformation of temperature field actually. In orderto simulate the work status of joints between new and old concrete blocks, thejoint rod element is used in this thesis. Because the element stiffness matrixcan be written out directly, so the joint rod element is useful and effective.