Abstract The computation of surrounding rock pressure of 60 m span flat underground cavern is beyond the
scope of the existing calculating methods. The empirical formulas and influencing factors are compared and analyzed. Based on Protodyakonov formula, the concept of process load and construction method, the cross section of cavern with super large span is divided into several small span caverns, and the surrounding rock pressure of super large span flat underground caverns is obtained considering the construction process. The relationship between the settlement of crown and the distance from the excavation face, the range and its maximum value of ground surface settlement caused by the advance of excavation are obtained by three-dimensional numerical simulation using finite difference method. Taking the εz of 0.000 25 as the critical strain, the loose scope and pressure load of surrounding rock are obtained. By comparing the calculation results of the three methods(one-cycle construction, process load and numerical calculation) it can be seen that the pressure value of surrounding rock obtained by applying the existing empirical formula directly is larger than the process load value and the numerical calculation result, while the numerical calculation result is similar to the process load value. Therefore, the process load has certain reference signifi?
cance for the calculation of the surrounding rock pressure of the super large span flat underground cavern.
Abstract：
The computation of surrounding rock pressure of 60 m span flat underground cavern is beyond the
scope of the existing calculating methods. The empirical formulas and influencing factors are compared and analyzed. Based on Protodyakonov formula, the concept of process load and construction method, the cross section of cavern with super large span is divided into several small span caverns, and the surrounding rock pressure of super large span flat underground caverns is obtained considering the construction process. The relationship between the settlement of crown and the distance from the excavation face, the range and its maximum value of ground surface settlement caused by the advance of excavation are obtained by three-dimensional numerical simulation using finite difference method. Taking the εz of 0.000 25 as the critical strain, the loose scope and pressure load of surrounding rock are obtained. By comparing the calculation results of the three methods(one-cycle construction, process load and numerical calculation) it can be seen that the pressure value of surrounding rock obtained by applying the existing empirical formula directly is larger than the process load value and the numerical calculation result, while the numerical calculation result is similar to the process load value. Therefore, the process load has certain reference signifi?
cance for the calculation of the surrounding rock pressure of the super large span flat underground cavern.
SUN Yulong YAN Zhiguo
.Study on Computation of Surrounding Rock Pressure of Super Large Span and Flat Underground Cavern Based on Process Load Concept[J] MODERN TUNNELLING TECHNOLOGY, 2020,V57(5): 91-98
2020, Vol. 57 