| With the rapid development of road tunnel project in our country, the features of long, large and deeply buried have become more evident, because of line and space constraints, the tunnels built in the weak and broken rock are more and more, in the construction process of the tunnels, the floor heave phenomenon occurred frequently. This paper combines with the practical engineering of Taoshuya tunnel, the engineering properties and the mechanical properties of soft-weak surrounding rock, the characteristics of floor heave and the main influencing factors, as well as the forms and the development process of floor heave in soft-weak surrounding rock tunnel and so on are discussed in detail. The floor heave problem is simplified as a plane strain problem to consider, using FLAC software for numerical simulation to explore several factors on the effects of floor heave deformation on the basis of the Hoek-Brown empirical strength criterion. Finally, the relative reasonable control technology of floor heave are proposed based on the mechanism analysis of floor heave and numerical simulation. In this paper, the main contents and the results are as follows:①The engineering properties and the mechanical properties of soft-weak surrounding rock are introduced in detail, the main influencing factors of floor heave deformation of soft-weak surrounding rock tunnel are analyzed, the forms and development process of floor heave are discussed.②The main reasons of floor heave deformation of Taoshuya tunnel are analyzed through field investigation, the rock mechanics parameters are estimated by using the Hoek-Brown empirical strength criterion based on the geological strength index (GSI), using FLAC numerical simulation software to calculate the floor heave vaules that the tunnel excavation without support as well as the original support, the plastic region range, the displacement and stress distribution of the tunnel surrounding rock are analyzed.③By using the FLAC software to simulation the floor heave deformation of tunnel for different GSI score, the disturbance factor D and coefficient of lateral pressure, their impact on tunnel floor heave deformation are analyzed. At the same time, the four Hoek-Brown empirical strength criteria parameters of the rock uniaxial compressive strengthσci, the geological strength index (GSI), the rock material constant m i and the disturbance factor D have been studied using the sensitivity analysis method.④The control technology of tunnel floor heave are introduced based on the mechanism analysis of floor heave and numerical simulation, the full-face bolt support, full-face grouting with roof and sides bolt support, full-face bolt and grouting support three control programs are proposed, through numerical simulation to further explore the effect of their support, which offer guidance for the select of appropriate control measures of floor heave.
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