Statistical analysis of surrounding rock pressure of mountain road tunnels

The relationships among span, depth, rock grades and vertical surrounding rock pressure are discussed based on the monitoring data of a large number of highway tunnels. A comparative analysis is made for obtaining the relationship between the measured and calculated values of the surrounding rock pressure. And the distribution regularities of lateral pressure, lateral pressure coefficients and secondary lining pressure are statistically analyzed under the conditions of every rock grade. The lateral rock pressure increases slowly with the growth of the depth and rock grade. The lateral pressure coefficient increases with the growth of rock grade and is larger than code value. The load sharing ratio of the secondary lining is consistent with the code.