The pretreatment mechanism of tunnels and its calculation method based on the incomplete arch effect
YE Fei1，FAN Kangjia1，SONG Jing1，DUAN Zhijun1，JIA Tao2
(1. School of Highway，Chang?an University，Xi?an，Shaanxi 710064，China；2. Beijing Urban Construction Design
and Development Group Co.，Ltd.，Beijing 100037，China)
Abstract：In the tunnel excavation，the deformation of the soil core in front of the surface of tunnel excavation may stimulate the arch effect in the surrounding soil ahead of the tunnel face. This kind of arch effect is different from the one produced behind the tunnel face and is called the incomplete arch effect. The performance of the incomplete arch effect is closely related to the pre-convergence deformation and extrusion. The formulas for calculating the soil pressure around the front soil core considering the incomplete arch effect are proposed and are different from Terzaghi formula，because in the proposed method，an angle between the fracture face and vertical direction is assumed and the effect of the pre-convergence deformation on the surrounding soil pressure and the non-vertical sliding surface effect of cohesive soils are taken into consideration. The results show that as the increase of the pre-convergence deformation，the earth pressure exhibits three stages：the rapid near-linear decrease，the slow decrease and the stable ones. The earth pressure decreases with the increase of internal friction angle，thickness-span ratio and cohesion. However，the earth pressure increases with the increase of the angle of rupture surface. The formula for calculating the reinforcement parameters of the front soil core based on ADECO-RS is deduced and its applicability is verified in a case study.
叶 飞1，樊康佳1，宋 京1，段智军1，贾 涛2. 基于不完全拱效应的隧道预处理机制与计算方法[J]. 岩石力学与工程学报, 2017, 36(6): 1469-1478.
YE Fei1，FAN Kangjia1，SONG Jing1，DUAN Zhijun1，JIA Tao2. The pretreatment mechanism of tunnels and its calculation method based on the incomplete arch effect. , 2017, 36(6): 1469-1478.
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2017, Vol. 36 
