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

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.