The seismic response of cable-stayed bridges is characterised by complicated interactions between the deck and the towers. These are influenced by the possible damage in the structure, and also by design choices or constraints such as the tower shape, the span, the cable arrangements, the support conditions and the type of foundation soil. The aim of this work is to assess the influence of these effects on the seismic behaviour of a large number of cable-stayed bridge finite element models. The results of the nonlinear dynamic analyses show the importance of the tower geometry. This is especially significant in short-span bridges with abrupt changes in the inclination of the lateral tower legs, which can lead to large levels of damage in the form of concrete cracking, reinforcement yielding and overall energy dissipation. Finally, design recommendations are proposed to improve the seismic response of the towers.

Thermal conductivity of frozen soil is a crucial property that influences heat transfer rate and freezing depth during the freezing process. However, accurately evaluating frozen soil's thermal conductivity is challenging due to its complex compositions and structures. To address this challenge, this study proposed the frozen soil quartet structure generation set (FSQSGS) to generate reasonable representative volume elements (RVEs) of frozen soil. The FSQSGS incorporates the ice phase and accounts for the freezing process, with clear physical meanings of input parameters. Then, the soil thermal conductivity of RVEs is calculated by the lattice Boltzmann method (LBM). This proposed calculation method is validated by experimental and analytical results of soil samples with various textures. The verification shows the broad applicability of the proposed model, especially for soils with fine grains or high saturation. Further, the influence of soil components and pore-scale geometry on the soil thermal conductivity is analyzed, with direct visualization of heat transfer. Results show that despite the soil skeleton geometry, i.e., the granular size and anisotropy, soil components have important effects on the soil thermal conductivity. Contents and thermal conductivity of soil particles are the main factors, while water and ice filling soil pores provide pathways for heat conduction, thereby improving thermal conductivity.

Aging and heavy rainfall can cause earth dams to undergo failure, which involves large displacements. Due to mesh distortion, however, the finite element method (FEM) is unsuitable for analyzing such large displacements. As an alternative, the material point method (MPM) ensures accurate simulation of large displacements, without the need for remeshing. This study uses MPM to investigate the post-failure behaviors of earth dams with various geometries and under different rainfall intensities. The MPM results are validated by comparing the MPM-derived pore water pressure with FEM-derived values for the same model, and a close alignment is confirmed. Different failure patterns are observed depending on the geometry and rainfall intensity. Under high water levels and rainfall conditions, the distributions and evolutions of the displacements and deviatoric strain are initially concentrated at the dam toe and gradually propagated from the downstream slope toe to the dam crest. Conversely, the distribution of pore water pressure remains relatively constant under high water levels, while rapid changes are observed under rainfall conditions. The runout distance, crest settlement, and sliding volume increase with increasing dam height, decreasing slope ratio, and increasing rainfall intensity. Therefore, MPM can be used as a promising tool for evaluating the entire failure mechanisms and post-failure behaviors of unsaturated earth dams.

Recently, bio-inspired technology utilizing the anisotropy of friction between structure-soil has garnered significant attention. In particular, new pile designs not only enhance shaft friction but also gain prominence by reducing the use of cement, which has traditionally been a key material in ground treatment and improvement. Previous studies have quantitatively verified the increase in interface shear resistance through direct shear tests and cone penetration experiments. However, conventional finite element analysis methods face limitations in analyzing the shaft friction behavior between piles with scale and the surrounding soil. In this study, the Coupled Eulerian-Lagrangian (CEL) technique, a large deformation analysis method built-in ABAQUS, is employed to simulate the penetration of cone with textured shaft. Numerical analyses are conducted to investigate changes in cone penetration resistance according to the geometric characteristics of the surface scale. To minimize numerical errors occurring in the cone and surrounding soil meshes, a three-dimensional generalized mesh is proposed for the cone and its surrounding elements. A total of 13 cases, comprising seven different cone designs and two penetration direction conditions, are analyzed. The results showed that under the same penetration load, penetration depth decreased as the scale height increased, the scale length narrowed, and the scale tapered in height.

Soil shrinkage during the drying process (water stress) is one of the main issues in expansive soils of paddy fields. It occurs due to decrease in soil water content, resulting in changes in soil volume and the geometry of pores, leading to the formation of cracks and higher water loss. The aim of this study was to assess the shrinkage characteristic curve and pore size of paddy soils to determine the shrinkage -swelling behavior in Guilan province, Iran. 120 soil samples were collected from the study area. Pore size was determined using soil moisture retention curve (SMRC). It was established by plotting the soil water content (theta) versus the corresponding matric suction (h), and the shrinkage curve by plotting the void ratio (e) against the moisture ratio (upsilon). The suction-pore relationships were also determined. Furthermore, the geometric factors indicating the change in vertical (subsidence) and horizontal (crack) volume of the soils were determined and varied from 1.23 to 2.53, indicating that the vertical change in soil volume is predominant. The zero, residual and proportional shrinkage phases accounted for less than 2 %, 8-38 %, and 61-91 % of the total soil volume change, respectively. The shrinkage capacity of the soils ranged from 0.52 to 1.37. Cation exchange capacity and clay content were identified as the most important factors affecting soil shrinkage properties. In general, the studied paddy soils have great potential for swelling- shrinkage and cracking during the drying process due to the large percentage of expandable clays and the medium to fine pores. The resultant cracks negatively affect crop yield by damaging plant roots and increasing water losses through the soil profiles.

Double-layer dike foundation is composed of a weakly permeable overlying clay layer and a highly permeable underlying sand layer, which is one of the most common stratum types in dike engineering with the highest probability of catastrophic damage, and the main danger is backward erosion piping. Existing research on backward erosion piping of double-layer dike foundation has not fully considered the influence of the exit on the erosion process. Therefore, a self-designed test device is used to assess the influences of the size, position and type of different exits, and the circular exit is connected with the slot exit via the exit area to explore the critical identification conditions and the pipe development mechanism toward the upstream direction under different exit geometry conditions. The results show that both the local and global hydraulic gradients borne by the exit are inversely proportional to the exit area and are less notably affected by the location of the exit. The development process of slot exit pipes differs from that of circular exit pipes, and pipes are usually developed alternately at the two corners of the exit near the upstream end and then converge into one pipe. The average pipe depth and width are proportional to the exit size and the seepage length. With increasing average pipe area of the slot exit, pipes develop more rapidly after head enhancement, and the damage to the dike foundation increases.

The longitudinal seismic response characteristics of a shallow-buried water-conveyance tunnel under non-uniform longitudinal subsurface geometry and obliquely incident SV-waves was studied using the numerical method, where the effect of the non-uniform longitudinal subsurface geometry due to the existence of a local one-sided rock mountain on the seismic response of the tunnel was focused on. Correspondingly, a large-scale three-dimensional (3D) finite-element model was established, where different incidence angles and incidence directions of the SV-wave were taken into consideration. Also, the non-linearity of soil and rock and the damage plastic of the concrete lining were incorporated. In addition, the wave field of the site and the acceleration response as well as damage of the tunnel were observed. The results revealed the following: (i) a local inclined subsurface geometry may focus an obliquely incident wave due to refraction or total reflection; (ii) a tunnel in a site adjacent to a rock mountain may exhibit a higher acceleration response than a tunnel in a homogeneous plain site; and (iii) damage in the tunnel in the site adjacent to a rock mountain may appear in multiple positions, and the effect of the incidence angle on the mode of compressive deformation and damage of the lining is of significance.

Slopes have a significant impact on the ground motion characteristics, which can aggravate the damage degree of building structures during a strong earthquake. However, many studies have focused on the design response spectra under flat site conditions and fewer researchers have investigated the impact of slope topography on the design response spectra. In this study, the numerical simulation is used to obtain the seismic response of slopes and the differential evolution algorithm is used to obtain the standardized response spectra of the acceleration time histories along the ground surface behind the slope crest. The impacts of slope height (H), slope gradient (i), average shear wave velocity in the top 30 m (VS30) and distance from the slope crest (x) on the characteristic parameters of the design response spectra are then investigated. The results show that H, i, VS30 and x have a little influence on the normalized second inflection point period (mean(Tg/Tg,ff)) but a great influence on the normalized plateau value (mean(alpha max/alpha max,ff)). Specifically, both mean(Tg/Tg,ff) and mean(alpha max/alpha max,ff) show a trend from increasing first to decreasing and stabilizing finally as x increases; the mean(alpha max/alpha max,ff) shows an increasing trend as H increases, but a decreasing trend as i or VS30 increases. Finally, to provide some guidance for the seismic design of building structures near slopes, two approximate relationships are proposed: (1) between mean(Tg/Tg,ff) and x, and (2) between mean(alpha max/alpha max,ff) and H, i, VS30, x. The main innovation of this paper is that the relationship between the characteristic parameters of the design response spectra and the slope site characteristic parameters is clearly summarized and quantified for the first time.

The construction of the 'Dayangyun' Expressway has generated a large number of engineering landslide disaster chains, mainly due to the lack of consideration of the influence of soil sediment anisotropy and slope geometric characteristics on slope stability, instability risk, and failure characteristics. It is urgent to propose a reasonable geometric optimization design method for slopes to prevent the occurrence of such disasters. This study established a random field model that incorporates rotational anisotropy-related structures of strength parameters. Subsequently, the slope reliability index(beta) was computed to evaluate slope stability. Additionally, failure modes were classified, introducing the shallow failure probability (PL) to assess failure risk. Finally, a comprehensive probability analysis framework with two indexes(the beta and PL) was designed to determine the optimal platform width of the slope(Lopt), and two slope cases were utilized for research and application purposes. The results indicate that rotation angles(theta) and platform width (L) significantly impact slope stability and instability risk. As the theta increases, the beta and PL exhibit S and M shaped trends, respectively. Specifically, the beta and PL display a logarithmic and exponential increasing trend with the increase of the L, respectively, this trend determines the Lopt. The dual-index comprehensive probability analysis framework can be employed to assess slope excavation stability and risk, as well as optimize slope geometry design. The research results can be used to prevent the occurrence of excavation slope disasters.

Freeze-thaw cycles (FTC) are known to have an effect on railway track stability, safety, and performance. FTC are expected to become more frequent in the future due to climate change. This paper presents the results of a field investigation in which the mechanism of FTC development within the track embankment and its effect on the performance of railway tracks including track surface deformation and track geometry degradation are studied. Field observations suggested that the frost depth within the track embankment is influenced by the freezing index and winter snow cover. They also showed that a warmer and drier winter leads to more intermittent FTC and even though the average frost heave is lower than for a colder winter, the frost heaves occurring at culvert locations creates a larger differential deformation and thus may lead to a worse operating condition. The comparison of geometry measurements before freezing and after thawing indicated that the track geometry is in poorer and rougher condition during springs that were preceded by increased FTC. It was also concluded that track in proximity to culverts suffered the highest geometry degradation. Overall, the limited field observations of this study suggest that future winters, mild with less precipitation and higher occurrence of FTC, may increase the rate of track deterioration and more maintenance will be required to keep track within safe limits.