Study On Bearing Capacity Of Weathered Rock Foundation In Fuxi Tunnel Of Tongling-Huangshan Expressway

In recent years, the double-arch tunnel has been widely used in vehicular tunnel construction, which has new structural style and many other advantages. Because of its large span and difficulty in design and construction, the bearing capacity of the rock foundation under the middle wall must be high enough for the complicated forces on it. For the reason that the rock mass in the south of Fuxi tunnel is broken up fiercely which is influenced by faultages and weathering effect, both its bearing capacity and deformation can't satisfy the need of design. The paper mainly studies on the geological engineering characters of the breaking weathered rock foundation in Fuxi tunnel, and then uses the methods of theoretical calculation and on-the-spot load tests to get its bearing capacity and prove whether it can fulfill the design of the tunnel. Firstly, based on the analysis of geological construct background and characteristics of rock mass in the location of the tunnel, the bearing capacity of the rock foundation is estimated primarily. Secondly, the paper calculates the ultimate bearing capacity by using and comparing two kinds of theories. Finally, we use load test to measure the real bearing capacity, through the analysis of test results we get the conclusion that the real bearing capacity of the rock foundation can't meet the need of tunnel design and the foundation must be reinforced. At the same time, according to the comparison between test results of different test spots and the theoretical ultimate bearing capacity, the paper lists the suggested value of safety factors in the area, which can also be used for reference to other similar constructions in the area of Huangshan.