Study On Construction Mechanics Of Twin-arch Tunnel In Shallow And Bias Rocks Under Yulingguan Antique City-wall

With the rapid development of higher highway since 1990s, there have been an increasing number of road tunnels in our country. Due to the special relief in narrow mountainous zone, as well as the high cost of and the difficulty in applying separate tunnel line, twin-arch tunnel is adopted. New Austrian Tunneling Method combined with field monitoring measurement are employed in the currently-built twin-arch tunnels to conduct dynamic design and information construction, which brings about fruitful economic and social benefits.Based on Yulingguan twin-arch Tunnel, the author regards the structural design of tunnel as relatively reasonable by virtue of analyzing the results of tunnel field monitoring measurement, while some aspects of tunnel construction still remain to be improved. Thus, two 2D Elastic Finite-Element Models of tunnel are respectively established, both of which go through I Wall-rock Sector andâ…¡Wall-rock Sector by means of large-scale Finite Element Software ANSYS. Thereby, the magnitude of wall stress, displacement, submergence of arch roof and terrestrial sedimentation in tunnels will be attained via numerical simulation of the whole construction process. Meanwhile, it is found that the mid-board stress is appropriate with overall compression yet partially with small tension stress through analyzing the results of the completed construction. In addition, the left-bolting execution of tunnel will severely affect the comprehensive construction stability owing to the existence of the lean stress. Hence, much attention should be paid to the safety of left-bolting construction. Furthermore, the strength of wall rock directly influences the integral stability of tunnel structure and naturally the tunnel sections of well-formed wall rocks embrace good stress and stability.What's more, this paper takes the effect of crown wall rock and mid-board foundation reinforced parametric variation on tunnel structure stress and stability into account grounded on building Typical Section Model of I Wall-rock Sector. Besides, Typical Section Model ofâ…¡Wall-rock Sector is built together with considering four different kinds of excavation in order to carry out the plane numerical simulation research of construction mechanics. Also, 40m-length fore-and-aft antique city walls will be utilized to establish the 3D Elastic Finite-Element Model. In this case, a reasonable construction technique will be attained as the impact of tunnel construction on terrestrial sedimentation of antique city-wall sectors as well as the stability of mid-...