Simulation Analysis On Cutterhead And Cutter Cutting Of Shield Machine In Sandy Cobble Stratum

With the development of the tunnel and underground space in our country, shield tunnel construction technology has been widely used. However, it has not yet formed perfect design theory of shield machine at present. When shield machine excavates in sandy cobble stratum, the stress in the cutterhead and cutter is very complicated, the abrasion is serious, and stratum is easy to collapse. In order to grasp the stress conditions of the cutterhead and cutter when shield machine excavates in sandy cobble stratum, optimize the design of the cutterhead, improve geology adaptability and drivage efficiency of cutter head of shield tunneling machine, This paper-funded by the national natural science fund " the dynamic interaction mechanism of action of the cutterhead and rock and soil and the design theory of the cutterhead system (51105048)"-completes the main work as follows:1. Through the investigation, shield tunnel construction technology in sandy cobble stratum and research status and research emphasis of the cutter cutting soil are studied. The characteristics of sandy pebble stratum and the instance of shield construction in sandy cobble stratum of our country are analyzed. The structural style of cutterhead and cutter and the configuration of cutter suitable for sandy cobble stratum are researched. On this basis, commonly problems and solutions are summarized according to the construction experience.2. Using3D modeling software Pro/E, a three-dimensional entity model of cutterhead and cutter of shield machine is established, and the finite element model of cutterhead and cutter is also established using ANSYS. The cutting force of shield cutters is calculated, and the static finite element analysis of cutterhead and cutter of shield machine under different excavating condition in sandy cobble stratum are respectively done, and the stress and strain distribution is concluded. Then the measures are researched and put forward on improving the durability of the cutterhead and cutter.3. The three-dimensional finite element model of cutter cutting soil in sandy cobble stratum is established by using dynamic analysis software ANSYS/LS-DYNA, and the soil constitutive model suitable for soil cutting is selected, then the dynamic simulation on cutter cutting is done. The mechanics change rule of contacting process between the cutter and soil in different cutting speed, cutting depth and distance between cutters is researched. The simulation results arrive at that:The contact force increases with the increase of cutting depth of cutter, the influence of cutting speed on cutter contact force is not big, the cutter contact force has increasing trend with the increase of distance between cutters, but the increase is small. The cutter contact force is decreased obviously comparing double cutters cooperative work with single cutter working in the same excavating parameters. The results provide the reference on the selection of layout design of cutterhead and cutter and reasonable excavating parameters for sandy cobble stratum.