Study On The Structural Mechanism Of Open TBM Main Engine And The Adaptability Of Turning Radius Of Small Curve

Hard rock Tunnel Boring Machine(TBM)can be divided into shield TBM and open TBM according to the structural form,open TBM is widely used in various hard rock tunnel boring operations because of its unique structural characteristics and engineering adaptability.In recent years,with the continuous advancement of TBM technology and the continuous expansion of its application fields,new fields require TBM with better turning performance and small turning radius to adapt to complex and changeable boring environments.Due to the lengthy rigid length and complex mechanism configuration of the existing models,TBM has problems such as too large minimum turning radius,difficult operation,and low excavation accuracy in the process of small-curve turning direction diversion,so that it cannot meet the requirements of small-curve turning radius tunnel construction.Therefore,the main engine structure mechanism and kinematics of the traditional horizontal main beam type and the new V-type TBM are studied,and based on the water diversion channel project of Shandong Wendeng Pumped Storage Power Station,the factors affecting the minimum turning radius of the open TBM are analyzed by establishing an open TBM turning direction model.Secondly,the horizontal main beam TBM and V-type TBM mainframe with a diameter of Ф3530 mm are improved,and the reachable working space of the cutter head under the V-type TBM two propulsion system configurations is solved based on Monte Carlo method.Finally,the relationship between the displacement and velocity change between the cutter head and the propulsion cylinder under the straight-line boring condition and the small curve turning boring condition of TBM under the linear boring condition and the small curve turning boring condition is analyzed by ADAMS software,and the following conclusions are obtained:(1)By analyzing the relationship model between the host and the surrounding rock when TBM turns and adjusting direction,the main factors and generality calculation formulas of horizontal main beam TBM and V-type TBM affecting the minimum turning radius are derived.(2)When the horizontal main beam TBM and 6-SPS V TBM are pitched and adjusted,the minimum turning radius that the mechanism can achieve is different;The 8-SPS V-type TBM has the same minimum turning radius when pitching and yaw steering.The horizontal main beam TBM small curve turning performance is poor,and the minimum turning radius is greater than 100 times the hole diameter;V-type TBM has good turning performance,and the minimum turning radius is less than 10 times the hole diameter.(3)When the turning radius of the tunnel design axis is large and most of the straight sections are the main segments,the TBM propulsion system of horizontal main beam has higher excavation efficiency;The V-TBM cutter head attitude change is more flexible and more suitable for complex and changeable small curve cornering.(4)For V-type TBM,the working space of the center point of the cutter head of the8-SPS propulsion system is greater than that of the 6-SPS propulsion system,and the 8-SPS propulsion system is symmetrical,and the speed of each cylinder changes more gently during the turning process,so the cylinder attitude of the mechanism is easy to control during the turning and propulsion process,the excavation accuracy is higher,and the propulsion system compliance is better.The research results provide a reference for the selection of small-curve TBM propulsion system,the arrangement of oil cylinders and the construction of small-curve TBM.