The Structural Selection And Design Analysis Of Cable Tunnel

With the development of economy and the progress of society, traditional power ducts, cable ducts, buried cable can not satisfy the requirements for the production, so we need to improve laying conditions of cable tunnel. More and more attention is paid on cable tunnel to ensure the safety of it and the beauty of city. So the selection and design of cable tunnel are very important.In view of the extensive collection of design schemes for cable tunnel both at home and abroad, the selection and design of cable tunnel for city have been studied. The main works and achievements are given in the following.1. Based on the actual geological condition of some cable tunnels, the cable tunnel discussed in the thesis has been divided into four situations in accordance with the depth, from 1km to 3km, Shallow rocky, named ZK1; from 3km to7.5km, Shallow soil, named ZK2; from 7.5km to 11.6km, deep rocky and groundwater, named ZK3; from 11.6km to 15.6km, deep soil and groundwater, named ZK4. Aimed at the above situations, the mechanical model of the cable tunnel which constituted by lining and peripheral soil is established in the thesis, various section forms and section sizes are proposed by integrating the concept of the project cost and project safety. The stress strength and deformation analysis of the cable tunnels in four depths are done to pick over the best section form by using the finite element method.2. The section size of cable tunnel is determined according to technological requirements of the electric cable layout and the convenience of the tunnel construction, operation and management. But with the change of geological data, situations and security levels, the section size is different. In the thesis, the finite element method is used to analyze mechanical and strength performance of cable tunnel and surrounding soil. In order to reduce the cost, the most suitable thickness of the tunnel is ensured according to the results of analysis.3. In order to ensure the safety of the project, dynamic response analysis of cable tunnel under earthquake actions is done. The computed results show that the tensile stresses of the concrete in the cases of the small and middle earthquake are less than the allowable tensile stress. Thus the tunnel structure is safety. However the tensile stress of the concrete in the large earthquake is more than the allowable tensile stress in which the concrete will be cracked. The tunnel structure needs to be firmed.The results about the structural selections and designs of cable tunnels obtained in the present thesis could be acted as reference for the design of the similar cable tunnel engineering.