Abstract In order to study the behaviour of high loess slope excavated and supported with different reinforcement modes,a series of centrifuge tests were conducted to simulate the high loess slope at the entrance of Guanyintang tunnel,considering the excavations without the reinforcement,with the full-section soil nailing,and with the soil nailing at the upper part and the pre-installed stabilizing pile at the lower part(pile-soil nailing structure) respectively. The pile-soil nailing structure was found to improve greatly the stability of the high loess slope in the tests. The soil nails at the upper part mobilized effectively a much wider area of loess slope to deform. The inward migration of the potential sliding surface led the toe of potential sliding surface be lowered to the position below the top of the pre-installed stabilizing piles. As such,the pre- installed stabilizing piles at the lower part can effectively bear the thrust force exerted by soil slope and guarantee the stability of loess slope during excavation. The stability of the loess slope was improved to certain degrees in the case of the full-section soil-nailing. However,when potential sliding surface surpass the reinforcement region of the soil nailing,the soil slope collapses eventually. Therefore,the combined structure of pile-soil nailing is better than the full-section soil nailing for the reinforcement of high loess slope.
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Received: 28 May 2013
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