دانلود رایگان مقاله لاتین تونل زنی سپر و حفاظت از محیط زیست در زمین نرم از سایت الزویر
عنوان فارسی مقاله:
تونل زنی با سپر و حفاظت از محیط زیست در زمین نرم شانگهای
عنوان انگلیسی مقاله:
Shield tunneling and environment protection in Shanghai soft ground
سال انتشار :2009
بخشی از مقاله انگلیسی:
2. Prediction of settlement and its effect on environment
To ensure the safety of environment in close proximity to shield tunnel, the theoretical prediction jointed with experiences on ground movement should be done before construction. In the prediction, GVLR and correspondent construction parameters of shield should be assumed in order to guarantee the predicted ground movement be within allowable limits of adjacent buildings and facilities under the assumed conditions. The study made below combining both domestic and abroad achievements with Shanghai metro tunneling practice focuses on the special ways of solving problems in crossing old buildings and running subway tunnels in Shanghai soft ground. In settlement prediction, 3D numerical modeling with Elasto– Plastic constitutive law and Drucker–Prager criterion is applied. The ground volume loss is simulated with equivalent gap parameters and the grouting process is simulated by volume expansion elements. The segmental tunnel lining is simulated with shell element with equivalent stiffness regarding the joint effect (Liao et al., 2008a). 2.1. Settlement Prediction for case SCBA 2.1.1. Prediction and monitoring requirements It is common sense that detail environment investigations include two parts: the first is about the building, its relative location and initial status as well as geological conditions, and the second is the near surroundings of the building, such as underground structures, obstacles, pipelines, especially the important /or dangerous pipes (gas pipes). The two parts form the integrity of boundary conditions which imply not only the adding of control items but also their interactions. It should be stressed and clarified here that complication lies in the interaction between the two parts in the control implementation due to their different response to the shield tunneling. In the project example here, the residential building is five-storey masonry structure, built in 50 years ago, and has inclined for 1.7% before construction as seen in Fig. 1. The external walls have been severely weathered. Apparent aging effects on buildings have been observed on the internal load bearing walls and beams. In addition, there are two pipelines (D300 gas pipe and D300 water supply pipe) situated closely along the building foundation edge at the side of tunnel. Three-dimensional modeling is applied in the ground movement prediction (Fig. 2) and the material properties applied in the model are listed in Table 2. The stiffness of the building is ignored but the initial stress produced by self-weight (100 kPa) of the building in ground is introduced by initial analysis. The structure elements are considered ideal elastic and the ground is regarded as elasto–plastic with Drucker–Prager criterion applied. GVLRs of 1‰, 3‰, 5‰ and 10‰ are assumed, respectively, to modeling different construction conditions. The maximum settlement and inclination of buildings can be obtained from analysis results as seen in Fig. 3. By safety assessment and critical analysis on the building, the additional allowable inclination of 3.5‰ is obtained. Based on the above prediction and assessment, the allowable GVLR, the maximum settlement of building and inclination of load bearing walls is determined as 5‰, 10 mm, 3.5‰, respectively. Field measurement results show that the settlement of building is in good accordance with the predicted under the assumed parameters (Fig. 4).
Geotechnical Aspects of Underground Construction in Soft Ground: ... https://books.google.com/books?isbn=0203879988 Charles W.W. Ng, H.W. Huang, G.B. Liu - 2008 - Technology & Engineering a. shield. tunnel. in. soft. clay. in. Shanghai. Z.P. Lu & G.B. Liu Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai, P.R. China Department of Geotechnical Engineering, Tongji University, ... adjusted to meet the requirement of environmental protection. SHAO-MING LIAO geotec.tongji.edu.cn/selfpage/liaoshm/Liao-shaoming-english.htm 2. Shao-ming, Liao( Dept. of Geotechnical Eng. , Tongji Univ. );Jian-Hang,Liu;Ru-Lu,Wang. Shield Tunneling and Environment Protection in Shanghai Soft Ground. Source:Tunnelling and Underground Space Technology. 24(4): 454-465, July, 2009. (SCI&EI index). 3. Peng, Fangle; Siddiquee, M.S.A.; Liao, Shaoming. [PDF]Performance of overlapped shield tunneling through an integrated ... https://cecas.clemson.edu/geomechanics/papers/Yang2017-US.pdf by J Yang - Cited by 2 - Related articles Apr 26, 2017 - b Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China c Glenn ... Abstract. In this work, deformations and internal forces of an existing tunnel subjected to a closely overlapped shield tunneling are monitored ...... tunneling and environment protection in Shanghai soft ground.