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Experimental study on face instability of shield tunnel in sand
Highlights ► Model tests were conducted to study the classical problem of tunnel face stability. ► Limit support pressure increases with the increase of the cover depth and then tends to be constant. ► Significant soil arching effect was revealed during tunnel face failure. ► A two-stage failure pattern was proposed based on the observation of earth stress.
Abstract Face stability is critical for ground settlement and construction safety control in shield tunneling. In this paper, a series of 3D large-scale model tests with a tunnel of 1m diameter were conducted in dry sand for various cover-to-diameter ratios C/D =0.5, 1, and 2 (i.e., relative depth; C is the cover depth and D is the diameter of tunnel). Each test provided a measurement of the support pressure and the ground settlement with the advance of face displacement. The evolution of soil arching during face failure was investigated by monitoring the redistribution of earth pressure in front of the face in the test case of C/D =2. In the displacement-controlled face failure tests in the medium density sands, the support pressure dropped steeply to the minimum value, then increased to a steady state with the continuing increase in the face displacement. Relationships between the support pressure and face displacement for various cover depths were also verified by the numerical analysis using the finite difference program, FLAC3D (Itasca, 2005). The limit support pressure increases with the increase of the relative depth C/D and then tends to be constant. A significant rotation of principal stress axes in the upward arches in the soil during face failure was found in the tests. A two-stage failure pattern is proposed based on the observation of earth pressure. The theoretical and empirical formulas for estimating limit support pressure were verified by the tests results.
Experimental study on face instability of shield tunnel in sand
Highlights ► Model tests were conducted to study the classical problem of tunnel face stability. ► Limit support pressure increases with the increase of the cover depth and then tends to be constant. ► Significant soil arching effect was revealed during tunnel face failure. ► A two-stage failure pattern was proposed based on the observation of earth stress.
Abstract Face stability is critical for ground settlement and construction safety control in shield tunneling. In this paper, a series of 3D large-scale model tests with a tunnel of 1m diameter were conducted in dry sand for various cover-to-diameter ratios C/D =0.5, 1, and 2 (i.e., relative depth; C is the cover depth and D is the diameter of tunnel). Each test provided a measurement of the support pressure and the ground settlement with the advance of face displacement. The evolution of soil arching during face failure was investigated by monitoring the redistribution of earth pressure in front of the face in the test case of C/D =2. In the displacement-controlled face failure tests in the medium density sands, the support pressure dropped steeply to the minimum value, then increased to a steady state with the continuing increase in the face displacement. Relationships between the support pressure and face displacement for various cover depths were also verified by the numerical analysis using the finite difference program, FLAC3D (Itasca, 2005). The limit support pressure increases with the increase of the relative depth C/D and then tends to be constant. A significant rotation of principal stress axes in the upward arches in the soil during face failure was found in the tests. A two-stage failure pattern is proposed based on the observation of earth pressure. The theoretical and empirical formulas for estimating limit support pressure were verified by the tests results.
Experimental study on face instability of shield tunnel in sand
Chen, Ren-peng (Autor:in) / Li, Jun (Autor:in) / Kong, Ling-gang (Autor:in) / Tang, Lv-jun (Autor:in)
Tunnelling and Underground Space Technology ; 33 ; 12-21
10.08.2012
10 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Experimental study on face instability of shield tunnel in sand
| Online Contents | 2013
Experimental study on face instability of shield tunnel in sand
| British Library Online Contents | 2013
Experimental investigation and limit analysis of shield tunnel face failure mechanism in sand
| Elsevier | 2025