The gap between the theoretical solution of the load and the field measurement is too large to guide the support design while the primary support of deep-buried soft rock tunnels shares a large surrounding rock load. In this study, the flexible support effect of the primary support and the rheological effect of the surrounding rock were considered. The calculation procedure of load shared by the primary support when the surrounding rock is in the accelerated, uniform velocity and decelerated stages was proposed. Then, the reliability of the computational method of the study was verified by numerical simulation methods. The analysis shows that the surrounding rock in the accelerated, uniform and decelerated stages of the load sharing of the primary support presents increasing, unchanged and decreasing states and that the formation of the primary support load is mainly concentrated in the stage of accelerated movement of the surrounding rock. Enhancement of the primary support parameters, while significantly increasing the support safety factor, has a limited effect on reducing load shared by the primary support. Thus, it is recommended that the advanced support can be strengthened to reduce the pre-deformation of the surrounding rock in the unsure soft rock section to reduce the load shared by the primary support. The primary support design of tunnels with rheological rock should account for the long-term rheological load effect of the surrounding rock. The results of this study can provide guidance for the prediction of primary support load sharing for dynamic tunnel construction.

深埋软岩隧道初期支护承受较大的围岩荷载，荷载理论解与现场实测差距过大，无法指导支护设计。本研究考虑了原生支护的柔性支护效应和围岩的流变效应。提出了围岩处于加速、匀速和减速阶段时主要支护所分担荷载的计算程序。然后，通过数值模拟方法验证了本研究计算方法的可靠性。分析表明，围岩在初期支护荷载分担的加速、均匀和减速阶段呈现增加、不变和减少状态，初期支护荷载的形成主要集中在支护加速运动阶段。围岩。提高主支撑参数虽然显着提高了支撑安全系数，但对于减少主支撑分担的荷载作用有限。因此，建议在不确定软岩地段加强超前支护，减少围岩预变形，以减少初期支护分担的荷载。流变岩隧道的初期支护设计应考虑围岩的长期流变荷载作用。研究结果可为动态隧道施工主支护荷载分配预测提供指导。