A critical investigation of three constitutive models for clay by means of analyses of a sophisticated laboratory testing program and of centrifuge tests on monopiles in clay subjected to (cyclic) lateral loading is presented. Constitutive models of varying complexity, namely the basic Modified Cam Clay model, the hypoplastic model with Intergranular Strain (known as Clay hypoplasticity model) and the more recently proposed anisotropic visco-ISA model, are considered. From the simulations of the centrifuge tests with monotonic loading it is concluded that all three constitutive models give satisfactory results if a proper calibration of constitutive model parameters and proper initialisation of state variables is ensured. In the case of cyclic loading, the AVISA model is found to perform superior to the hypoplastic model with Intergranular Strain.

This study focuses on the behaviour of buried gas pipelines subjected to surface loading. The study is oriented towards an experimental campaign carried out on small-scale pipelines, with three different wall thicknesses, both in monotonic and cyclic conditions. Pipes have been instrumented with strain gauges and inner displacement sensors, allowing to record deformations, stresses and ovalisation of the pipe, in addition to the load-settlement relationship at the soil surface. Results show that the presence of the pipe affects the global soil response (stiffness and bearing capacity). Analysis of the strain distribution and pipe deformed shape indicate that the pipe response is complex, with no symmetry along the horizontal axis, and a heart-shaped deformation pattern. The pipe rigidity affects the local behaviour at the pipe level (displacement pattern, evolution of stresses during cyclic loading and increasing lateral support). Classical pipeline design theory has been assessed based on the experimental observations, invalidating several underlying hypotheses.

Marine soft clays are known for their poor engineering properties, which, when subjected to prolonged static and dynamic loading, can lead to excessive settlement of offshore pile foundations and subsequent structural instability, resulting in frequent engineering failures. This study examines the bearing and deformation behavior of jacked piles in these clay deposits under both static and cyclic loading conditions using a custom-designed model testing apparatus. Emphasizing the time-dependent load-carrying capacity and accumulated cyclic settlement of piles, the research uses artificially structured clay to more accurately simulate stratum conditions than traditional severely disturbed natural clays. Model pile testing was carried out to analyze the effects of soil structure and cyclic loading patterns on the long-term response of jacked piles. Key factors investigated include initial soil structure, pile jacking-induced destruction, soil reconsolidation post-installation, disturbed clay's thixotropic effects, and cyclic loading's impact during service. Results show that increasing the cement content within the clays from 0 % to 4 % nearly doubled pile penetration resistance, led to a more significant accumulation of excess pore water pressure (EPWP), and accelerated its dissipation rate. Additionally, the ultimate load-carrying capacity of jacked piles also doubled. Higher cement content slowed pile head settlement rates and reduced stable cumulative settlement values, requiring more cycles to reach instability. Under high-amplitude, low-frequency cyclic loads, hysteresis loops of the model piles became more pronounced and rapid. This study enhances understanding of the long-term cyclic behavior of jacked piles in soft soils, providing valuable insights for designing offshore piles.

Cyclic loads induced by environmental factors such as wind, waves, and currents can lead to degradation in pile performance, affecting settlement accumulation and bearing capacity evolution. This paper presents a comprehensive investigation through model tests focusing on a single pile subjected to static and cyclic loading in medium-dense sands. The influence of installation method, diameter, cyclic load amplitude, and loading frequency on pile response was explored, particularly emphasizing the accumulation pattern of pile head settlement and the evolving laws governing pile shaft and end resistance. The findings illustrate that the radial stress at the pile shaft 400 mm away from the pile end increases to 3.27 times its initial stress after pile jacking. As pile diameter increases, the accumulative settlement rate decreases, highlighting the soil-squeezing effect on cyclic stability. Small cyclic loads gradually densify soil around the pile end, increasing pile end resistance, while larger cyclic loads rapidly reduce both pile end and shaft resistance. Under high-amplitude, low-frequency cyclic loading, the load-settlement hysteresis characteristics of model piles intensify, with the hysteresis loops moving more rapidly in the deformation direction.

Although Novel Polymeric Alloy (NPA) geocells have been applied to stabilize road bases against the freeze-thaw (F-T) damage in practice, the relevant research lags the application. A scarcity of research has been reported to comprehensively evaluate the benefits of geocell stabilization in enhancing the F-T performance of bases. This study aims to investigate quantitatively the F-T performance of geocell-stabilized bases, focusing on two influencing factors-i.e., water supply and degree of compaction in the bases. A series of model-scale experimental tests (19 tests) was conducted using an upgraded customized apparatus. The results showed that the inclusion of geocells was beneficial for reducing frost heave and thaw settlement as well as mechanical properties (i.e., stiffness and ultimate bearing capacity) of road bases. The benefit of geocells was more remarkable for the well compacted bases than for the poorly compacted bases. The benefit was more pronounced in the open system than in the closed system.

This study investigates the deformation characteristics of geosynthetic reinforced soil (GRS) bridge abutment models under cyclic loading conditions through experimental methods. The GRS abutment models were built using well-graded sand as backfill material and biaxial geogrid for reinforcement. Settlements of the footings, displacements of the facing, and strains in the reinforcements were monitored and analyzed. The findings show that cumulative settlements increase as the cyclic load amplitude rises. Furthermore, facing displacement tends to increase with height, reaching its maximum at the top. The cyclic loading amplitude affects the strains in the upper reinforcements more significantly than those in the lower reinforcements.

Back-to-back MSE walls are a novel use of reinforced soil technology, and they are frequently implemented for bridge approaches and width-restricted highway and railway embankments. Urbanization has, however, led to an increase in the construction of transportation infrastructures. An investigation on model back-to-back MSE walls supporting railways has been carried out on a strong clay foundation. The foundation soil was clay with the desired shear strength. The model was conducted with a scale of 1/10th supporting railway tracks. Geogrid was used as a reinforcement, and wooden blocks were used as modular blocks for wall facings. The effects of different overlapping methods and distance between both walls on wall behavior have been evaluated. The scarcity of usable natural backfill soil for construction has been an alarming concern. Thus the recycled waste coal mine over dump was used as subballast/backfill soil. The coal mine overburden dump was used as a sustainable alternative to natural backfill/subballast. Cyclic loading simulating train loadings have been simulated in the model tests. Connected case of the model test was conducted in the laboratory. A finite element comparison of the model tests has also been conducted. A parametric study was carried out on back-to-back MSE walls subjected to heavy axle loads. Artificial intelligence-based ensemble models were used to predicted the geogrid tensile forces obtained from the parametric study.

Intense summer rainstorms can result in short-term urban flooding, leading to localized groundwater level rise and subsequent floor cracking and leakage in basements. Rational control of the surrounding water level is crucial for addressing existing basement leaks caused by short-term urban flooding. In this study, a combined approach of interception and seepage control using waterproof curtains and negative-pressure wells is proposed. Four different scenarios were considered, and experimental and numerical investigations were conducted on a 1.2 m x 1.2 m x 1.1 m model. The study analyzed the influence of factors such as water content, pore water pressure, soil properties, waterproof curtain insertion depth, and length of the filter in the negativepressure well on controlling the upward water level in the basement. The results showed that the installation of waterproof curtains alone can impede rainwater infiltration into the basement, delaying its penetration by approximately 48 h. The combined approach of interception and seepage control outperformed the sole use of waterproof curtains, with the reduction in water level becoming smaller as the insertion depth of the waterproof curtain increased. The reduction in water level decreased at a slower rate with increasing waterproof curtain insertion depth. The recommended waterproof curtain insertion ratio was equal to or greater than 83.5 %, while the filter length ratio in the negative pressure well should be less than 64 %. Compared to natural seepage drainage, negative-pressure pumping could maintain the basement floor's water content within the initial range 32 h earlier. The water-blocking and depressurization effect is best in sandy soil and worst in clay. Water-blocking and depressurization provide a new approach for controlling the uplift caused by summer urban waterlogging, especially offering a new method for controlling leaks in the basement.

Geofoam, when substituting soil, reduces lateral static load due to its lightweight and compressible nature. The alignment and the orientation of the geofoam greatly affect the deflection of the wall. This paper investigates the influence of different geofoam orientations on the load-deformation characteristics of the reinforced retaining wall. Static load tests were performed when sand or geomaterial prepared from sand, bottom ash, and plastic strips were used as a backfill material. Different orientations were explored when geofoam of densities 11D, 16D, and 34D where D is the density of geofoam were laid in different directions. A layer of compressible inclusion with a thickness of 10 cm was laid either in the vertical direction alone or in both vertical and horizontal directions. Another option was to use a 10-cm-thick geofoam laid in the vertical direction and geofoam strips of thickness 2, 3, or 5 cm laid in layers. The reinforcement effect was analyzed using bearing capacity ratio, vertical displacement reduction, and wall deflection reduction. Results indicated that higher-density geofoam is more efficient in reducing settlement values and increasing bearing capacity. Lower-density geofoam excelled in wall deflection reduction. The most substantial improvements were observed for 10-cm-thick 16D geofoam laid in the vertical direction, accompanied by 5-cm-thick strips laid in three layers in the horizontal direction. This combination reduced the settlement and wall deflection to 78.23% and 98.81%, respectively.

On March 11, 2011, the Great East Japan Earthquake triggered tsunamis that reached extensive areas along Japan's Pacific coast. There have been instances where embankments built on plains for expressways mitigated the impact of tsunami damage. In the vicinity of the Sendai-tobu highway, the presence of an embankment approximately 10 m high altered the course of the advancing tsunami, thereby preventing flooding. Establishing a multiplied defense system using road embankments necessitates understanding the deformation and collapse mechanisms of road embankments impacted by tsunamis following seismic motion. In this study, overtopping experiments were conducted by first applying seismic motion to model embankments, followed by introducing the first wave of breaking bores, and then simulating prolonged overtopping by the tsunami. The experimental findings indicated that within the embankments impacted by the tsunami, there was an immediate increase in what is presumed to be pore air pressure following the arrival of the breaking bores, followed by a rise in pore water pressure during subsequent overtopping. Moreover, embankments subjected to seismic motion exhibited accelerated erosion following the overtopping. These results imply that when embankments settle due to an earthquake, leading to relatively higher anticipated inundation depths and the potential for overtopping, it is crucial to implement measures to prevent the settlement of the crest for embankments expected to serve as part of a multiplied defense system.