Calculation method of surrounding rock pressure for shallow and unsymmetrical tunnel under deep valley terrain

Code for design of road tunnel provides the calculation method of surrounding rock pressure for shallow and unsymmetrical tunnel, however, which has the applicable condition. Based on code method, the critical edge width is derived which need satisfy when using code method. Then, by assuming the retaining wall model, the analytical solution of lateral pressure for shallow and unsymmetrical tunnel under deep valley terrain is deduced. At last, taking Lijiabao tunnel belonging to Zhangzhuo highway as engineering relying and combining with the field measurement of surrounding rock pressure, the conclusion is drew by comparisons that the value from method in this paper is more close to the reality than the code method. The study results provide references with the design and construction of similar engineering and offers favorable supplement for the current code.