A number of underground structures have experienced significant damage in recent large earthquakes. Generally, underground structures have significant dimensions, pass through different strata, which lead to seismic response of underground structures invokes the needs for large scale computing compared with multi-shaking table tests. It is widely accepted by researchers that simplified structural analysis cannot provide the whole understandings of its dynamic performance. A multiscale approach is developed to analyze the dynamic properties of both experiment and in-site underground structures.

 

Objective: A multiscale numerical method with high accuracy and affordable computational cost is developed to simulate multiscale dynamic problems for large underground structures. A multiscale testing method is proposed to capture multi-point seismic responses of the integral soil-structure system and describe in detail the dynamic response in positions of potential damage or interest under non-uniform seismic loadings.

 

Approach: The multiscale method is established to couple coarse / fine FEMs or discontinuous DEM / continuous FDM, based on the bridging domain method. The multiscale testing method includes a small-scale multi-shaking-table test on the integral soil-structure system and a large-scale pseudo-static test on the critical positions.

 

Significant Results and Potential Impact: This multiscale modeling method does not result in spurious wave reflections and does not need additional filtering or damping in the overlapping subdomains. This method can significantly reduce the computational load. It adequately covers wide simulation areas of the entire structure-soil system but may also include details in key locations of underground structures. The multiscale testing technology is first developed for long tunnels subjected to non-uniform excitations, which solves the critical issue on how to convert the discrete multi-point seismic input into the continuous seismic input.

 

Principal Investigator: 

 

Yong Yuan, and H.T. Yu

 

      Funding: National Natural Science Foundation of China (51208296), National Key Technology R&D Programs (2011BAG07B01 and 2012BAK24B04).

 

Key Publications:

 

      1) Li M.G., Yu H.T., Yuan Y., et al. A multiscale coupling approach between discrete element method and finite difference method for dynamic analysis. International Journal for Numerical Methods in Engineering, 2014. (SCI) IF: 2.068.

 

      2) Yu H.T., Yuan Y. Analytical solution for an infinite Euler-Bernoulli beam on a visco-elastic foundation subjected to arbitrary dynamic loads [J]. Journal of Engineering Mechanics, ASCE, 2014, 140(3): 542-551. (SCI) IF: 1.116.

 

      3) Yu H.T., Yuan Y., Yu G.X., Liu X. Evaluation of influence of vibrations generated by blasting construction on an existing tunnel in soft soils [J]. Tunnelling and Underground Space Technology, 2014, 43: 59-66. (SC) IF: 1.106.

 

      4) Yu H.T., Yuan Y., Qiao Z.Z., Gu Y., Yang Z.H., Li X.D. Seismic analysis of a long tunnel based on multi-scale method [J]. Engineering Structures, 2013, 49: 572-587. (SCI) IF: 1.713.

 

      5) Yu H.T., Yuan Y., Bobet A. Multiscale method for long tunnels subjected to seismic loading [J], International Journal for Numerical and Analytical Methods in Geomechanics, 2013, 37(4): 374-398. (SCI) IF: 1.055.

 

      6) Yu H.T., Yuan Y., Liu X., Li Y.W., Ji S.W. Damages of the Shaohuoping road tunnel near the epicenter [J], Structure and Infrastructure Engineering, 2013, 9(9): 935-951. (SCI) IF: 2.805.

 

      7) Chen Z.Y., Yu H.T., Yuan Y. Full 3D seismic analysis of a long-distance water conveyance tunnel [J], Structure and Infrastructure Engineering, 2014, 10(1): 128-140. (SCI) IF: 2.805.