In order to obtain the seismic dynamic characteristics of a shallow-bias tunnel with a small space, a series of large-scale shaking table model tests were carried out. The key technology of the test is introduced in detail, for example, similar ratios of model, test equipment, testing model box, testing model, sensor arrangement, seismic waves, and testing system. The results show that the first predominant frequency is similar between measuring points. However, the second predominant frequency is highly different between measuring points. The first and second predominant frequencies gradually decrease with the increasing of input PGA. The rock stratum can shield seismic wave in the high frequency band. The research results provide reference for similar tunnels.

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Dynamic vulcanization was successfully applied to epoxy resin reinforced polypropylene (PP)/ethylene-octene copolymer (POE) blends, and the effects of different compatibilizers on the morphology and properties of dynamically cured PP/POE/epoxy blends were studied. The results show that dynamically cured PP/ POE/epoxy blends compatibilized with maleic anhydridegrafted polypropylene (MAH-g-PP) have a three-phase structure consisting of POE and epoxy particles dispersed in the PP continuous phase, and these blends had improved tensile strength and flexural modulus. While using maleic anhydride-grafted POE (MAH-g-POE) as a compatibilizer, the structure of the core-shell complex phase and the PP continuous phase showed that epoxy particles could be embedded in MAH-g-POE in the blends, and gave rise to an increase in impact strength, while retaining a certain strength and modulus. DSC analysis showed that the epoxy particles in the blends compatibilized with MAH-g-PP were more efficient nucleating agents for PP than they were in the blends compatibilized with MAH-g-POE. WAXD analysis shows that compatibilization do not disturb the crystalline structure of PP in the blends.

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Based on the similarity theory, two physical testing models (double-hole tunnel and single-hole tunnel) with a scale of 1:10 were designed and manufactured. A series of shaking table tests followed by numerical simulations was carried out to obtain the dynamic response characteristics of shallow-buried tunnels with asymmetrical pressure distributions. The similarities and differences in the dynamic response laws between double-hole tunnel and single-hole tunnel were studied. The effects of types of seismic wave (Wenchuan wave, Darui artificial wave, and Kobe wave), peaks acceleration excitation (0.1 g, 0.2 g, 0.4 g, and 0.6 g), excitation directions (horizontal and vertical directions), and excitation modes (unidirection and bidirection) on dynamic response laws of the tunnels were studied. The results show that the variation of acceleration multiplying factor (AMF) shows a nonlinear trend. The AMFs are different at different monitoring points. The type of seismic wave has a significant effect on the acceleration response, with Kobe wave being the most serious, followed by the Darui artificial wave and the Wenchuan wave. In bidirectional excitation, the AMFs are relatively larger than those of unidirectional excitation. A comparison between the numerical simulation and the shaking table tests in both acceleration time history and peaks acceleration shows that the results of the shaking table tests and numerical simulations are credible. The acceleration response of monitoring points near the existing slope is generally magnified. The residual strains are generated at the monitoring points. The variation trends of both tensile strain and compressive strain are opposite. The tensile strains are generally larger than the compressive strains. Many factors, such as the type of seismic wave, peaks of acceleration excitation, excitation direction, and excitation mode, have a significant influence on the dynamic strain response and acceleration response of the tunnels. The research results could promote the understanding of dynamic response characteristics of the tunnels.

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In order to reveal the acceleration response law of shallow-buried bias double-arch tunnel under earthquake. The acceleration response of the shallow-buried biased double-arch tunnel under the action of Wenchuan wave was studied by the combination of shaking table test and numerical simulation. The effects of non-bias and bias on the acceleration response of shallow-buried biased double-arch tunnels were discussed. Research indicates: (1) Horizontal acceleration amplification factor of the left-hole (non-biased side) for the shallow-buried biased double-arch tunnel is V-shaped, and the right-hole (bias side) is ∩-shaped. The vertical acceleration amplification factor of the left-hole tends to increase continuously, and the right-hole shows a trend of decreasing first and then increasing continuously. (2) In the state of both the bias and the non-biased tunnel, the acceleration response in the vertical direction is stronger than that in the horizontal direction. (3) In the two states of bias and non-bias, the difference between the horizontal and vertical acceleration amplification factors of the double-arch tunnel is larger. It indicates that the excitation direction of the seismic wave has a great influence on the acceleration response of the double-arch tunnel. (4) Relatively biased double-arch tunnels, the regularity of non-biased double-arch tunnels is better, indicating that the bias voltage has a greater impact on double-arch tunnels.