In this paper, through extensive on-site research of the plain concrete composite foundation for the Jiuma Expressway, the study conducted proportional scaling tests. This study focused on the temperature, moisture, pile-soil stress, and deformation of this foundation under freeze-thaw conditions. The findings indicate that the temperature of the plain concrete pile composite foundation fluctuates sinusoidally with atmospheric temperature changes. As the depth increases, both temperature and lag time increase, while the fluctuation range decreases. Furthermore, the effect of atmospheric temperature on the shoulder and slope foot is more significant than on the interior of the road. During the freeze-thaw cycle, the water content and pore-water pressure in the foundation fluctuate periodically. The pile-soil stress fluctuates periodically with the freeze-thaw cycle, with the shoulder position exhibiting the most significant changes. Finally, the road displays pronounced freeze-thaw deformations at the side ditch and slope toe. This study provides a valuable basis for the construction of highway projects in cold regions.

Loose sandy soil layers are prone to liquefaction under strong earthquakes, causing damage to civil engineering structures inside or upon the liquefied ground. According to the present Japanese design guideline on liquefaction countermeasures for river levees, the entire depth of the liquefiable subsoil below river embankments should be improved. However, this approach is not economical against deep liquefiable subsoil. To rationalize the design approach, this contribution investigated the performance of a floating-type cement treatment method, in which only the shallower part of the liquefiable subsoil is reinforced. A series of centrifuge shaking table model tests was conducted under a 50g environment. The depth of improvement (cement treatment) was varied systematically, and the effect of the sloping ground was examined. The experimental results revealed that the settlements of river embankments can be reduced linearly by increasing the depth of improvement. Moreover, the acceleration of embankments can be reduced drastically by the vibration-isolation effect between the cement-treated soil and the liquefiable soil. These effects contribute to the safe retention of the embankment shape even when the liquefied sloping ground causes lateral flows. Towards practical implementation, discussions on the effect of permeability on cement-treated soil were expanded. Furthermore, the stress acting on cement-treated soil during shaking was measured using an acrylic block to explain the occurrence of cracks in the soil. (c) 2025 Japanese Geotechnical Society. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

A series of large-scale (1:13) model tests of multi-stage loading and unidirectional multi-cycle loading were conducted on semi-rigid piles before and after cement-soil reinforcement in clay. The difference of ultimate bearing capacity between unreinforced and reinforced piles under different criterions is discussed, and their bending moment and displacement distribution rules are revealed. Meanwhile, the cyclic bearing behaviour of the unreinforced and reinforced piles are compared and analyzed, including cyclic load-displacement response, unloading stiffness, cumulative peak & residual displacement, peak & locked in moment. The test results show that the ultimate bearing capacity of the large diameter pile is increased by 34.4 % and the initial stiffness is increased by 56.8 % (reinforced width is 3D and depth is 1D) in the multistage loading test. Comparing the monotonic and cyclic load-displacement curves of unreinforced and reinforced piles obtained by multi-stage loading test and unidirectional multi-cycle loading test respectively, it is found that when the applied load is small, the curve obtained from multistage loading test is almost coincident with the first cycle envelope of all load levels in 1-way multi-cycle loading test, indicating that the cyclic effect is not significant. As the load increases, the difference between the curves becomes larger, indicating that the cyclic loading of higher amplitude causes greater soil disturbance. In addition, after applying cement-soil to the shallow soil around monopile, cement-soil reinforced pile exhibits a more rigid response, specifically manifested as an initial unloading stiffness of 1.76 times that of unreinforced pile, and a slower stiffness degradation rate. Meanwhile, the cyclic peak displacement & residual displacement accumulation of reinforced piles are smaller than that of the unreinforced pile, thereby reducing the development of the locked in moment.

Earthquake-induced soil liquefaction causes ground and foundation failures, and it challenges the scientific community to explore the liquefaction problem in deep deposit under strong shaking. Due to the capacity limitation of physical modelling facility, it is difficult to reproduce soil liquefaction response of deep sand ground by centrifuge shaking table test. To address this problem, a suite of centrifuge model tests were conducted with the aid of Iai's Type III generalized scaling law (i.e., GSL) to observe the liquefaction response of deep sand ground, where Models 1 and 2 were used to validate the GSL and Model 3 with the validated GSL stands for the deep sand ground with prototype depth of 80 m. The test results of Models 1 and 2 indicate that GSL generally performs well for small-strain shear modulus, nonlinear dynamic response of acceleration and the generation of excess pore water pressure, but leaves considerable errors for post-shaking dissipation process and ground settlement with large plastic strain. The test results of Model 3 indicate that liquefaction is also possible in depth of 30-40 m under shaking event of PBA = 0.4 g and Mw = 7.5. For deeper depth without triggering of liquefaction, a depthdependent power function relationship between the peak excess pore water pressure and Arias intensity has been established. The test results also revealed that consolidation and earthquake shaking history contribute to the development of soil anisotropy in a deep ground, leading to a continuous increase of anisotropy degree, which could be evaluated using the small-strain shear moduli in different stress planes under orthogonal stress conditions.

Stone columns are a resultful measure to increase the bearing capacity of soft or liquefiable foundations. The centrifuge model test and finite element method were employed to investigate the bearing capacity and deformation behavior of the stone column-reinforced foundation. Study shows that the modulus of the reinforced foundation exhibits significant anisotropy. A bulging deformation area is identified in the reinforced foundation where obvious horizontal deformation of the stone column occurs. The ratio of the column stress and soil stress is observed to change violently in this area. A homogenization technique is consequently deduced by employing the column-soil stress ratio as a key variable. The definition of the column-soil stress ratio is extended to reasonably describe the column-soil interaction under different stress levels and its approximation method is given. Based on the Duncan- Chang E-nu model, a simplified method using the homogenization technique is proposed for the stone column reinforced foundation. The proposed homogenization technique and simplified method have been validated by the centrifuge model tests and finite element analyses. This method properly addresses the nonlinear spatial characteristic of deformation and the anisotropy of the stone column reinforced foundation.

This study investigates the mechanical performance and deformation characteristics of reinforced retaining walls constructed with stabilized silty clay and geogrid reinforcement. Laboratory tests evaluated the physical and mechanical properties of native silty clay, identifying its high water content and poor gradation as primary challenges for engineering applications. A stabilization method incorporating 2 % soil stabilizing liquid, 10 % densifying powder, and 4 % Portland cement was optimized to enhance clay compaction, shear strength, and compressive strength. Model experiments were conducted under varying wall configurations, including natural slopes, stabilized retaining walls, and reinforced stabilized walls with different slope ratios. Results show that the combination of stabilization and reinforcement significantly improved load-bearing capacity, minimized vertical settlement, restricted horizontal displacement, and reduced lateral earth pressure. Comparative analysis of slope ratios revealed that gentler slopes enhanced deformation resistance and reduced geogrid strain. These findings offer practical insights and theoretical support for designing efficient retaining wall systems using stabilized silty clay.

Climate change has intensified the occurrence of rock-ice avalanches, heightening risks to communities and infrastructure in alpine regions. However, their abrupt onset and remote locations have limited investigations into their initiation mechanisms. This study addresses that gap through centrifuge experiments based on two major events: the 2000 Yigong landslide in China and the 2021 Chamoli rock-ice avalanche in India. These models represent distinct rock wedge failure types and allow comparative analysis of freeze-thaw cycles and glacier-rock interactions. Results reveal that frost heave and pore water pressure fluctuate parabolically with temperature during freeze-thaw cycles, contributing to significant displacement and stress changes prior to failure. The presence of overlying ice and meltwater infiltration accelerates initiation by weakening rock-ice bonding and altering hydraulic conditions along discontinuities. These findings provide new experimental evidence on the mechanics of rock-ice avalanche initiation and offer insights for early warning systems and risk mitigation in cold, high-relief environments.

Steel slag is an environmentally friendly material with significant potential as an alternative to gravel for encased columns in soft ground improvement. However, the performance of composite foundations improved by geosynthetic-encased steel slag columns (GESSC) remains somewhat unclear. This study compares the working performances of GESSC and geosynthetic-encased stone column (GESC) composite foundations, as well as untreated foundations, through a series of large-scale experiments. Additionally, cone penetration tests were conducted on both the untreated and GESSC foundations to assess changes in soil strength before and after loading. The results show that both GESSC and GESC significantly increase the bearing capacity of soft clay, demonstrating an approximate 10-fold increase compared to the untreated foundation. The GESSC composite foundation marginally outperforms the GESC in bearing capacity during the elastoplastic stage. Furthermore, upon reaching the ultimate bearing capacity, the GESSC exhibits greater radial strain and less settlement than the GESC, owing to the unique redistribution of steel slag and gravel. Both types of foundations effectively transmit vertical pressure to deeper soil layers, with GESSC demonstrating superior load transmission capabilities and a more uniform distribution of soil stress along the depth. The excess pore-water pressure and its accumulation rate within the GESSC foundation are typically lower than those in the GESC composite foundations, underscoring the superior drainage capabilities of GESSC. This enhanced drainage capacity leads to a higher consolidation ratio within the soil, resulting in a significant improvement in soil strength after loading compared to the untreated foundation.

Tensile cracks play a pivotal role in the formation and evolution of reservoir landslides. To investigate how tensile cracks affect the deformation and failure mechanism of reservoir landslides, a novel artificial tension cracking device based on magnetic suction was designed to establish a physical model of landslides and record the process of landslide deformation and damage by multifield monitoring. Two scenarios were analyzed: crack closure and crack development. The results indicate that under crack closure, secondary cracks still form, leading to retrogressive damage. In contrast, under crack development conditions, the failure mode changes to composite failure with overall displacement. The release of tensile stresses and compression of the rear soil are the main driving forces for this movement. Hydraulic erosion also plays a secondary role in changing landslide morphology. The results of multifield monitoring reveal the effects of tensile cracking on reservoir landslides from multiple perspectives and provide new insights into the mechanism of landslide tensile-shear coupled damage.

Basalt fiber-reinforced polymer (BFRP) anchors are increasingly utilized in geotechnical anchoring engineering; however, there remains significant potential for studying the erosion characteristics of the BFRP anchor-slope system under rainfall conditions. This paper investigated the hydrological and spatial-temporal characteristics of three-level bridge foundation slope (TLBFS) reinforced by BFRP anchors through laboratory rainfall experiments. An index (rill density beta\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\beta$$\end{document}) was defined to quantify the degree of slope erosion. The experimental setup included a flume measuring 2 m in length, 1.2 m in width, and 1.5 m in height, a uniform rainfall intensity of 20.0 mm/h, and four sensors used for monitoring moisture content V, earth pressure E, anchor dynamometer T, and strain gauge S. The results indicated that the rill densities of third-level and first-level slopes after soil saturation were 2.37% and 0.98%, respectively. However, relying solely on the rill density index may lead to an overestimation of slope stability. Conversely, the high moisture content (25.72%) of the first-level slope correlated with its deformation and failure. It is proposed that the moisture content index can serve as a reliable indicator for evaluating slope stability. A strong correlation existed between moisture content omega\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\omega$$\end{document} and erosion amount delta\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\delta$$\end{document}, which suggested that real-time monitoring of slope erosion can be conducted using the moisture content index. The damage to TLBFS resulted from the coupling of the internal and external factors, and the specific failure mode was identified as shallow slip. While the flexible reinforcement capabilities of BFRP anchors effectively mitigated slope deformation, but additional engineering measures need to be added to TLBFS. These findings provide valuable insights for soil and water conservation and disaster prevention in multi-level slopes.