The study of the damage effects resulting from the explosions of cylindrical charges holds significant importance in both military and civilian fields. In contrast to spherical charges, the explosive characteristics of the cylindrical charge exhibited spatial irregularities. To comprehensively quantify the influences of borehole diameter and buried depth on the damage effects, including the crater size and stress wave, experimental and numerical investigations on explosions induced by cylindrical charge are carried out in this paper. Firstly, a set of tests is conducted to provide fundamental data. Then, based on the meshfree method of Smoothed Particle Galerkin (SPG) and the K&C model, the variations in crater dimensions and the peak stress are fully simulated with a range of borehole diameters and buried depths. Finally, the influence of borehole and buried depth on the coupling factor is discussed. Both the buried depth and the borehole diameter impact the utilization of blast energy enormously. Furthermore, materials with distinct impedance values exert an influence on the distribution of the stress wave. Following the dimensional analysis, several empirical formulae expressing the crater size and peak stress are established, all of which can predict explosion damage rapidly and accurately.

With the continuous expansion of urban underground space development, stratum disturbance induced by shield construction has an important impact on the safety of existing underground structures and surrounding environment. Through the independent research and development of the shield tunneling test device, the load of different stratum stress levels was realized, and the change law and influence range of the stratum disturbance in shield construction under different burial depth conditions were analyzed. The results show that the change rate of earth pressure in the strata around the tunnel decreases with the increase of the horizontal distance from the tunnel. The ratio of soil pressure after shield tunneling to initial soil pressure is about 60%-80%. The change of buried depth ratio has little influence on the soil stress path at the vault and bottom. The stratum disturbance degree based on the change of stress is defined, and the stratum disturbance degree gradually decreases with the increase of the burial depth ratio, indicating that the deep burial condition will reduce the disturbance effect of shield excavation on the stratum. After the completion of the shield tunneling, the height of the vertical influence range of the disturbance is between 0.5D and 0.8D above and below the tunnel (D is the diameter of tunnel), the width of the horizontal disturbance range is about 0.5D when the shield reaches the monitoring section, and approximately 1.2D to 1.5D when the shield passes far away.

Exploring the interaction of pipe-soil under frost heave effect is the key to solving the problem of frequent damage to buried pipes. In this study, the effects of ambient temperature (AT), buried depth of pipe (BDP) and initial water content (IWC) on the interaction of pipe-soil under the condition of roadbed frost heave are studiedby experimental test. The results show that the buried pipe seriously affects the soil temperature field and the migration of pore water during roadbed frost heaving. As the AT decreases, the final strain of pipes (FSP) gradually increases, and the flatness of the roadbed gradually deteriorates. When the BDP is 2D (outer diameter of the pipe), the flatness of the roadbed is the worst. The pore water in unfrozen area tends to migrate more toward soil around pipes during the roadbed frost heaving. The IWC of roadbed has a greater impact on the FSP than the BDP These could provide a guidance for the construction of pipes under frost heave in roadbed.

There are countless engineering disasters induced by expansive strata in the tunnel project. Nowadays, most of the research focuses on the basic characteristics of expansive rock and soil, while the influence about coupling buried depth and different initial water content of surrounding rock on the tunnel lining is still rarely involved. Based on the principle of temperature and humidity equivalence, this paper discusses the behavior of rock as well as the mechanical properties of lining under the interaction of different buried depth and initial water content by using FLAC(3D) numerical simulation. It was found that the initial water content shows an obvious effect on the evolution about the plastic area of rock compared with the buried depth of the tunnel. For shallow tunnels with a water content of less than 10 %, the plastic zone of the vault will penetrate to the surface after water absorption and expansion. Under the coupling effect, buried depth inhibits the development of the plastic zone to a certain extent. For different initial water contents of the surrounding rock, the displacement of the tunnel adds with the burial depth. The swelling of rock will significantly reduce the safety of the primary support, and when the burial depths of the tunnel increase to 150 m, the security coefficients of some primary support structures are less than 2, which does not meet the need in standard. The safety factor of secondary support is mainly influenced by the expansion force, not the ground pressure (represented by buried depth). The findings may be valuable reference for the analysis as well as evaluation of the security as well as stability of tunnels in expansive mudstone.