深埋高地应力隧道不同支护时机求解方法对比研究

为确定深埋高地应力隧道的合理支护时机，提高支护结构质量，降低支护成本，依托某高原深埋高地应力隧道，采用安全系数法、位移增量法和塑性区法分别求解支护结构的合理支护时机，并对比分析不同支护时机求解方法的适用性。

Comparative Analysis of Results of Various Methods to Determine Reasonable Support Timings of Deep Buried Tunnels with High Ground Stress

To rationally determine the support timing of deep buried tunnels with high ground stress, improve the support structure quality, and reduce the support cost, a case study is conducted on a deep buried plateau tunnel with high ground stress. Safety factor, displacement increment, and plastic zone methods are employed to determine the reasonable support timing of the support structure, and the applicability of each method is analyzed and compared. The results reveal the following. (1) The distribution laws of cave wall yield calculated by the three methods agree, it is easier to yield at the crown and invert than at the waist and foot. (2) The results of support timings by the various methods differ; under the same buried depth, the safety distance obtained by the safety factor method is greater than that obtained by the plastic zone and displacement increment methods. The engineering analogy shows that the plastic zone and displacement increment methods are more conservative than the safety factor method; thus, the safety factor method is recommended when determining the support timing.