Damage to underground structures caused by liquefaction is one of the important types of hazards in the field of geotechnical engineering. Utility tunnels are the lifeline projects of cities. To ensure the sustainable and safe operation of utility tunnels over a design life of 100 years, this paper investigates the seismic response pattern of utility tunnels in the liquefied site. In this paper, shaking table tests were carried out on the utility tunnel in a layered liquefiable site. Based on the test data, the distribution law of acceleration field and pore pressure field in the model and the deformation of the soil were analyzed first. Then the soil-structure interaction, the strain and uplift of the structure were investigated. The results show that liquefaction of sand layers under strong earthquakes, resulting in seismic energy loss. The acceleration of the upper clay layer is attenuated by the seismic isolation of the liquefied soil. The utility tunnel affects the propagation of soil acceleration, which decays faster beneath the structure for the same height. The process of pore water pressure growth is a process of energy accumulation and the pore water pressure ratio curve and Arias intensity are significantly correlated. During the test, the phenomenon of sand boil appeared, and the cracks appeared on the ground surface and developed continuously. The utility tunnel in liquefied soil is lifted under the action of excess pore water pressure. There are vertical and horizontal displacement differences at the deformation joints. The strain in the utility tunnel at the stratigraphic junction is mainly influenced by the action of the bending moment, large shear deformation in the transverse section. The strain at the connection between the partition wall and the top slab is the largest and is the weak position of the structure, followed by the connection between the side walls and the top slab, and the bottom slab of the structure have a smaller strain. The results provide insights into the dynamic properties of soils and structures in liquefaction sites.

Landslides are a typical geological hazard that can cause large numbers of casualties and huge economic losses, and the overflow of a weir from a blocked river landslide can have even more disastrous consequences. Of the different types of landslides, about 33% of landslides happen in anti-dip slopes. This paper reports a massive ancient anti-dip river-damming landslide on the Jinsha River: the Zongrongcun landslide. Field investigation and theoretical analysis were used to reveal the potential mechanism of this ancient landslide, and the block discrete element software 3DEC was used to replicate its landslide process. The findings from the present study are as follows: (1) blocks in this landslide were classified into significant slide, significant toppling, and significant slide categories based on D_f. (2) The whole landslide was divided into significant sliding and toppling zones by D_f = 0.5. (3) The results show that the river-damming landslide was likely to be triggered by river erosion, heavy rainfall, gravity. Under strong valley trenching, the rocks on the slope fractured under gravity and tectonic stress. These factors caused rock blocks tensile fracture failure. Then a penetrating sliding surface formed on the slope, which subsequently caused this river-damming landslide.

Damage to underground structures induced by soil liquefaction under cyclic loads such as earthquakes has long been an important issue in underground engineering practice. In this paper, five models are developed using Flac3D software to analyze the effect of burial depth on the force, deformation characteristics, and uplift behavior of utility tunnels in the non-homogeneous site containing a liquefied layer. The cyclic shear property of saturated sand and the increase in pore water pressure during the earthquake are modeled using a cyclic load-volume strain increment model, using Shell-Type structural elements to model underground utility tunnels, and by using plastic hinges to represent the bending moment capacity of member’s joints. Numerical results show that for shallow-buried utility tunnels, increasing the burial depth increases the bending moment, shear force, and deformation of the structure while significantly reducing its uplift. Therefore, for high-strength shallow-buried utility tunnels, appropriate increase in burial depth can improve its seismic safety.

In recent years, there has been a rise in the construction of expansive underground structures and shield tunnels with exceptionally large diameters. These projects introduce unique challenges regarding their impact on the surrounding soil and structures, which differ from those typically encountered in conventional shield tunnels. However, the existing body of research in this specific domain remains insufficient. When such tunnels intersect deep foundation pits supported by piled-raft foundations, the discrepancies in soil deformation can become even more pronounced. At present, there is a dearth of research on the underlying principles governing these differences, and theoretical investigations have not kept pace with practical engineering applications. Consequently, the existing settlement prediction methods employed for diverse projects need to be reevaluated and adjusted to accommodate the distinctive characteristics of each individual project. Regarding the engineering focus of this paper, it is crucial to recognize that soil subsidence in the pit bottom has a significant influence on the mechanical response of the piles. Consequently, the implementation of targeted correction measures remains consistently important. Based on this concept, this paper focuses on a super-large diameter shield tunnel project that under-crossed a deep foundation pit with a piled-raft foundation. The influence of different construction methods on the settlement law of the soil at the bottom of the deep foundation pit is discussed after verification of the accuracy of the model through numerical simulation and field monitoring data. Additionally, two correction coefficients that consider the project’s load characteristics are proposed in this research. These coefficients were used to correct the surface settlement curve. The corrected soil settlement curve at the pit’s bottom can successfully reflect the numerical simulation results, which in turn can reflect the mechanical response of the pile under the influence of tunnel excavation.

In the context of increasing environmental awareness and the demand for sustainable construction practices, the use of recyclable materials in civil engineering projects has gained significant attention. This study focuses on the bearing characteristics and deformation behavior of recyclable steel-pipe piles during the excavation of foundation pits. Field experiments and numerical simulations were conducted to comprehensively analyze the stress characteristics and surface settlement patterns behind the piles. The results reveal critical insights into the interaction between the steel-pipe piles and the surrounding soil, providing a detailed understanding of the stress distribution and deformation mechanisms. An empirical method for calculating the surface settlement value, induced by foundation pit excavation under the support of steel-pipe slope protection piles, has been proposed. This method improves the accuracy of settlement predictions and enhances the reliability of foundation pit design.