Physical model study on the mechanism of floor heave for the deep-buried roadway excavated in soft rock of gently inclined thin strata

Strata structure is an important factor affecting floor heave of deep soft rock roadway, however, the mechanism of floor heave induced by the rock structure has not been fully understood, so it is still necessary to study the floor heave of deep-buried roadway under different rock structure conditions.Thus providing further theoretical basis and scientific basis for the control of surrounding rock in mine tunnels. In order to study the floor heave mechanism of soft rock roadway deep-buried roadway excavated in soft rock of gently inclined thin strata, a physical model experiment based on the engineering geological conditions of typical mine roadway was carried out. During the experiment, CCD camera and strain acquisition system were employed to collect image data and strain data. Based on the analysis of the experimental results, the following conclusions are drawn: (1) For the soft rock roadway located in deep-buried thin rock stratum, horizontal stress is an important factor affecting the floor heave of roadway; (2) When the floor heave occurs in the roadway, the strain distribution of floor of roadway is funnel-shaped, the max VME strain value of the floor is near 0.19, the affected range of floor strata is about half of the roadway width; (3) The surrounding rock within one time of the tunnel diameter is in the state of tensile stress after the process of roadway floor heave failure, and the areas of tensile stress and compressive stress in the surrounding rock alternates around the roadway; The failure mechanism of floor heave of the roadway is the fracture and uplift of the floor of roadway. Besides, a numerical model was conducted to verify the results of the physical model, the results of numerical simulation are in good agreement with those of physical model.