高山融雪对浅埋偏压小净距隧道边坡稳定性的影响及处置措施

THE INFLUENCE OF ALPINE SNOW MELTING ON THE STABILITY OF SHALLOW BURIED BIAS PRESSURE AND SMALL CLEAR DISTANCE TUNNEL SLOPE AND ITS TREATMENT MEASURES

  • 摘要: 为研究高山融雪对浅埋偏压小净距隧道边坡稳定性的影响,依托新疆上新光隧道工程,基于折减系数法,将高山积雪等效为相应降水,运用数值模拟和现场实测相结合的方法,分析积雪融化对隧道洞口处边坡稳定性的影响,总结西部高寒覆雪地区小净距隧道边坡稳定性规律,并根据实际情况采取相应处置措施。结果表明:融雪入渗对边坡稳定性产生较大影响,雪水完全入渗后,边坡塑性区贯通,沉降量增大,最终沉降量达116.673 mm。积雪融化后边坡孔隙水压力增大,以边坡顶部和边坡底部最为明显,孔隙水压力最大值可达1.471 MPa;边坡安全系数随雪水入渗深度增加而减小,当雪水入渗深度达300 mm时,安全系数达到临界值1.05;采用抗滑桩对隧道边坡进行加固,能有效提升边坡稳定性,运用截水沟对融雪进行阻断,能有效减少雪水入渗量。

     

    Abstract: It studied the effect of alpine snowmelt on the stability of slopes in shallow buried bias small distance tunnels, based on the Xinjiang Shangxinguang Tunnel Project and the reduction coefficient method, through the assumption that the snow accumulation in high mountains is equivalent to corresponding precipitation. The method of combining numerical simulation and on-site measurement is used to analyze the impact of snow melting on the stability of slopes at the tunnel entrance, and to summarize the stability laws of small distance tunnel slopes in the western cold and snowy areas. And corresponding disposal measures shall be taken according to the actual situation. The results indicate that the infiltration of snowmelt has a significant impact on the stability of the slope. After the complete infiltration of snow water, the plastic zone of the slope penetrates and the settlement increases, resulting in a final settlement of 116.673 mm. After the melting of snow, the pore water pressure of the slope increases, with the top and bottom of the slope being the most obvious, and the maximum pore water pressure can reach 1.471 MPa. The safety factor of the slope decreases with the increase of snow water infiltration depth. When the snow water infiltration depth reaches 300 mm, the factor of safety reaches the critical value of 1.05. The use of anti slip piles to reinforce tunnel slopes can effectively improve slope stability, and the use of intercepting ditches to block snowmelt can effectively reduce the infiltration of snow water.

     

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