Mechanical Properties and Reinforcement Measures of Bedding Slope Slip at the Entrance of Soft Rock Tunnels in Southwestern Yunnan
Based on the entrance section of Manle No.1 Tunnel of Yumo Railway in the southwest Yunnan,the sliding failure of soft rock tunnel entrance under bedding condition and the corresponding reinforcement measures were studied.MIDAS GTS NX software was used to establish the three-dimensional model of the tunnel entrance before and after reinforcement,based on the mechanical characteristics of the portal front slope before and after reinforcement,the reinforcement measures of combining grouting anchor cables and frame beams were proposed.The results show that under the condition of not affecting the excavation of the tunnel,the cement mortar anchor cable can be inserted into the ground surface along the bedding rock normal direction for grouting reinforcement,which can reduce the compressive stress at the tunnel portal and front slope.The vertical displacement of front slope reduced by 14.26％,and the longitudinal displacement of the front slope is reduced by 43.57％,the stability coefficient of the front slope is 2.1.This reinforcement measure can resist the sliding of the front slope and enhance the stability of the tunnel portal and front slope.The reinforcement measures of combining grouting anchor cables and frame beams has achieved good results after being implemented on site,which can provide a reference for related projects.
soft rock tunnelbedding front slopeslope slipslope stabilityreinforcement measures
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