ISSN:
1662-9752
Quelle:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Thema:
Maschinenbau
Notizen:
Soil is a complex material whose properties are elastic, plastic and viscious. The selectionof a proper constitutive relation is important in the study of stratum movement induced byunderground excavation in modern cities. First, based on the Fast Lagrangian Analysis of Continua(FLAC) method, the elastic response stress (p, q) distribution induced by a circular tunnel is analyzed,and the surrounding soil is divided into four categories: p increase q increase, p increase q decrease, pdecrease q increase, p decrease q decrease according to p-q stress path. The character of p-qdistribution and the plastic zone induced by tunneling in clay are compared when the Mohr-Coulombmodel (M-C), the Drucker-Prager model (D-P) and the Modified Cam-Clay model (C-C) are adopted;the C-C model is considered to be suitable for simulating underground excavation problems. Second,factors such as stratum character, stress path and relative position between soil and excavation arethought to be important in the selection of a proper constitutive relation, accounting for the geologicalcondition of Beijing and measuring techniques being used in geotechnical engineering. Fine grainedsoils such as clay and silt can be modeled by the C-C model. Coarse grained soil, for containing andnot containing excavation, may be represented using the M-C model considering strain softening andthe normal M-C model. Finally, with the aid of FLAC method and its internal language FISH, ascheme of estimating and controlling parameter input is suggested
Materialart:
Digitale Medien
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/18/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.575-578.1358.pdf
