Deep soil mixing (DSM) is a widely used ground improvement method to enhance the properties of soft soils by blending them with cementitious materials to reduce settlement and form a load-bearing column within the soil. However, using cement as a binding material significantly contributes to global warming and climatic change. Moreover, there is a need to understand the dynamic behavior of the DSM-stabilized soil under traffic loading conditions. In order to address both of the difficulties, a set of 1-g physical model tests have been conducted to examine the behavior of a single geopolymer-stabilized soil column (GPSC) as a DSM column in soft soil ground treatment under static and cyclic loading. Static loading model tests were performed on the end-bearing (l/h = 1) GPSC stabilized ground with Ar of 9 %, 16 %, 25 %, and 36 % and floating GPSC stabilized ground with l/h ratio of 0.35, 0.5, and 0.75 to understand the load settlement behavior of the model ground. Under cyclic loading, the effect of Ar in end-bearing conditions and cyclic loading amplitude with different CSR was performed. Earth pressure cells were used to measure the stress distribution in the GPSC and the surrounding soil in terms of stress concentration ratio, and pore pressure transducers were used to monitor the excess pore water pressure dissipated in the surrounding soil of the GPSC during static and cyclic loading. The experimental results show that the bearing improvement ratio was 2.28, 3.74, 7.67, and 9.24 for Ar of 9 %, 16 %, 25 %, and 36 %, respectively, and was 1.49, 1.82, and 2.82 for l/h ratios of 0.35, 0.5, and 0.75 respectively. Also, the settlement induced due to cyclic loading was high under the same static and cyclic stress for all the area replacement ratios. Furthermore, the impact of cyclic loading is reduced with an increase in the area replacement ratio. Excess pore water pressure generated from static and cyclic loads was effectively decreased by installing GPSC.

Post-grouted shafts (PGDS) and stiffened deep cement mixed (SDCM) shafts reinforce the surrounding soils with cement to enhance the bearing capacity of shaft foundations, and their applications are becoming increasingly widespread. Field tests involving two post-grouted shafts and two stiffened deep cement mixing shafts were conducted at the bridge foundations projects, analyzing the vertical bearing performance of the shafts with cement-stabilized soil enhancement. Additionally, numerical simulations were performed to establish calculation models for single shaft and groups of drilled shafts, PGDS, and SDCM shafts, enabling a comparative analysis of their bearing capacity performance within the identical strata. The results indicate that the post- grouted shaft demonstrated significant bearing deformation capacity, as confirmed by field tests. After grouting, the ultimate bearing capacities of DS1 and DS2 improved by 124.5 % and 110.9 %, respectively. In both single and group modeling shaft foundations, the post-grouted shafts demonstrated the highest bearing deformation characteristics, followed by the identical- size stiffened deep cement mixed shaft, while the long-core SDCM shafts and the ungrouted shafts exhibited the weakest performance. Due to interaction effects among group shafts, the total bearing capacity of the group shafts is not simply the sum of the individual shafts. Specifically, the reduction factor for group shaft capacity ranges from 0.68 to 0.79 at the Baoying Large Bridge site, while at the Yangkou Canal Bridge site, it varies from 0.66 to 0.85. The findings of this study provide valuable insights for practical engineering applications.

This study utilizes a combined approach of Finite Element Method (FEM) simulation and Artificial Neural Network (ANN) modeling to analyze and predict the load-displacement relationship of bored piles in clayey sand. FEM is applied to simulate the nonlinear relationship between load and vertical displacement, with input parameters including load and the mechanical properties of the soil. The results obtained from FEM are used as input data for the ANN model, enabling accurate predictions of vertical displacement based on these parameters. The findings of this study show that the predicted ultimate bearing capacity of the bored piles is highly accurate, with negligible error when compared to field experiments. The ANN model achieved a high level of accuracy, as reflected by an R2 value of 0.9992, demonstrating the feasibility of applying machine learning in pile load analysis. This research provides a novel, efficient, and feasible approach for analyzing and predicting the bearing capacity of bored piles, while also paving the way for the application of machine learning in geotechnical engineering and foundation design. The integration of FEM and ANN not only minimizes errors compared to traditional methods but also significantly reduces time and costs when compared to field experiments.

Seismicity resulting from the near- or in-field fault activation significantly affects the stability of largescale underground caverns that are operating under high-stress conditions. A comprehensive scientific assessment of the operational safety of such caverns requires an in-depth understanding of the response characteristics of the rock mass subjected to dynamic disturbances. To address this issue, we conducted true triaxial modeling tests and dynamic numerical simulations on large underground caverns to investigate the impact of static stress levels, dynamic load parameters, and input directions on the response characteristics of the surrounding rock mass. The findings reveal that: (1) When subjected to identical incident stress waves and static loads, the surrounding rock mass exhibits the greatest stress response during horizontal incidence. When the incident direction is fixed, the mechanical response is more pronounced at the cavern wall parallel to the direction of dynamic loading. (2) A high initial static stress level specifically enhances the impact of dynamic loading. (3) The response of the surrounding rock mass is directly linked to the amplitude of the incident stress wave. High amplitude results in tensile damage in regions experiencing tensile stress concentration under static loading and shear damage in regions experiencing compressive stress concentration. These results have significant implications for the evaluation and prevention of dynamic disasters in the surrounding rock of underground caverns experiencing dynamic disturbances. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. 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/).

The soil-cement deep soil mixing (DSM) technique has been widely used to improve the bearing capacity of the soft soil under embankment loading. However, utilizing ordinary portland cement (OPC) releases a tremendous carbon footprint. Industrial waste-based geopolymer has emerged as a sustainable and environmentally friendly solution for stabilizing soft soils. This work investigates the behavior of embankment models constructed on geopolymer-stabilized soil columns (GPSCs) under static and cyclic loading conditions similar to transportation routes. A series of static and cyclic loading tests were carried out on the reduced-scale designed embankment model resting on soft soil (cus = 5 kPa) reinforced with end-bearing (l/h = 1) and floating (l/h = 0.75) GPSCs with area replacement ratios (Ar) of 12.7%, 17%, and 21.2% to analyze the vertical stress-settlement behavior of the improved ground. Earth pressure cells were used to measure the vertical stress on the column and the adjacent surrounding soil under static and cyclic embankment loading. A pore-pressure transducer was used to monitor the excess pore-water pressure generated during the loading process. The results indicate that the ultimate bearing capacity (qult) improvement for end-bearing GPSCs was 246.92%, 344.56%, and 418.8%, whereas the improvement for floating GPSCs was 126.9%, 151%, and 181.64% for Ar values of 12.7%, 17%, and 21.2%, respectively. Furthermore, the stress concentration ratio increases and excess pore-water pressure decreases with increasing Ar and l/h ratios. A mathematical equation was also derived to determine the qult value with Ar and l/h ratios. End-bearing GPSCs were more effective than floating GPSCs at the same Ar under static and cyclic loading. For installing floating GPSCs, a higher area replacement ratio is required for better load bearing under static and cyclic loading. In addition, a life cycle assessment of the geopolymer compared to OPC was performed, showing that the geopolymer is a sustainable and eco-friendly construction material.

In this study, six rock-socketed bored piles were tested in the field to investigate the bearing characteristics of rock-socketed bored piles in silty clay formations in coastal areas, and the model piles were simulated and optimized using the finite element (FE) method. The results showed that the lateral resistance of the piles in the clay layer is less than 50 kPa, and the lateral resistance of the rock-embedded portion is within 136.2-166.4 kPa. Compared with increasing the rock-embedded depth, increasing the diameter of the test piles can improve their vertical bearing capacity more effectively. The average horizontal critical load (Hcr) increased by 84.54 %, and the average horizontal ultimate load (Hu) increased by 50.3 % for the 800 mm diameter piles compared to the 600 mm diameter piles. Also, at the end of the test, the 600 mm diameter test piles showed severe damage at 6-9.5 D below the mud surface and were more susceptible to instability damage than the 800 mm diameter test piles. In soft clay strata, the 'm' values converged rapidly with increasing horizontal displacement and stabilized when the displacement exceeded 10 mm. The FE simulations confirmed that the horizontal displacement of the pile mainly occurs at 4 m depth below the mud surface, and the displacement of the test pile can be effectively reduced by reinforcing the soil around the pile. The silt at the bottom of the pile is one of the critical factors causing the uneven settlement of the test pile, severely affecting the vertical bearing capacity of the pile foundation.

As an innovative foundation used in the offshore floating platform, the scaled suction caisson (SSC) has a greater advantage in the installation and service than the traditional suction caisson (TSC). To investigate the pull-out capacity of the SSC, the numerical simulations are carried out under static and cyclic loads. The study shows the inclined pull-out capacity of the SSC increases with increasing the loading angle., but firstly increases, then decreases with increasing the padeye depth. Compared with the TSC, the inclined pull-out capacity of the SSC increases by 20 similar to 40% when the loading angles. are in the range of 0 similar to 30 degrees, but its values increase by 100% when the loading angles exceed 60 degrees. Under the combined static and cyclic loads, the vertical cumulative displacement of the SSC decreases, but horizontal cumulative displacement increases. The total cumulative displacement of the SSC decreases by 13% compared with the TSC. It can be concluded that more soils can mobilized by the bio-scale surface to resist the pull-out loads. As a result, the SSC significantly improves inclined pull-out capacity and decreases the cumulative displacement.

This paper presents a field pile load test program conducted on four 0.36 m closed-end steel pipe piles with lengths ranging between 11 and 13 m installed in fine-grained soils. Subsurface investigations with standard penetration tests and cone penetration tests with pore pressure measurements were performed at the site. Three pushed-in piezometers at incremental offsets from the piles were also installed to monitor pore water pressure changes during and after the installation of piles. Several dynamic load tests were performed at different times to observe the change in pile resistance. A static load test was also performed on one of the piles. Some load test results showed an unexpected decrease in the resistances of some piles with time. The study showed that construction activities, e.g., installation of other piles, disturbs the soil and groundwater conditions which can significantly affect the pile resistance measured during load tests. This investigation revealed that pile driving and restrikes should be scheduled such that the effect of construction activities on load tests results will be avoided or minimized.

Microbiologically Induced Calcite Precipitation (MICP) technology offers a promising method for stiffness reinforcement of offshore wind turbines (OWTs). However, edge scour around microbial reinforcement raises concerns about potential stiffness degradation. This study examines the effects of edge scour on the lateral responses of rigid piles reinforced with precast microbial reinforcement using a low-pH one-phase grouting method. Results from static tests, validated by numerical simulations, demonstrated that MICP technology bonded loose sand grains with the pile, forming a bio-reinforced pile with a larger diameter in the shallow soil layer, which significantly enhanced the original pile's bearing capacity and stiffness. However, edge scour reduced the embedment depth of the bio-reinforced pile, leading to a decrease in its bearing capacity and stiffness. Geometrically, protection width was found to have a relatively greater influence on stiffness and capacity compared to protection thickness. Additionally, symmetric cyclic loading tests were conducted to evaluate the effects of edge scour on backbone curves, secant stiffness, and damping ratio. Although MICP-based reinforcement notably enhanced both the secant stiffness and damping ratio of the piles, its effectiveness was completely lost once the scour depth reached the reinforcement thickness of the bio-reinforced soil block.

This paper presents an analysis of long, large-diameter bored piles' behavior under static and dynamic load tests for a megaproject located in El Alamein, on the northern shoreline of Egypt. Site investigations depict an abundance of limestone fragments and weak argillaceous limestone interlaid with gravelly, silty sands and silty, gravelly clay layers. These layers are classified as intermediate geomaterials, IGMs, and soil layers. The project consists of high-rise buildings founded on long bored piles of 1200 mm and 800 mm in diameter. Forty-four (44) static and dynamic compression load tests were performed in this study. During the pile testing, it was recognized that the pile load-settlement behavior is very conservative. Settlement did not exceed 1.6% of the pile diameter at twice the design load. This indicates that the available design manual does not provide reasonable parameters for IGM layers. The study was performed to investigate the efficiency of different approaches for determining the design load of bored piles in IGMs. These approaches are statistical, predictions from static pile load tests, numerical, and dynamic wave analysis via a case pile wave analysis program, CAPWAP, a method that calculates friction stresses along the pile shaft. The predicted ultimate capacities range from 5.5 to 10.0 times the pile design capacity. Settlement analysis indicates that the large-diameter pile behaves as a friction pile. The dynamic pile load test results were calibrated relative to the static pile load test. The dynamic load test could be used to validate the pile capacity. Settlement from the dynamic load test has been shown to be about 25% higher than that from the static load test. This can be attributed to the possible development of high pore water pressure in cohesive IGMs. The case study analysis and the parametric study indicate that AASHTO LRFD is conservative in estimating skin friction, tip, and load test resistance factors in IGMs. A new load-settlement response equation for 600 mm to 2000 mm diameter piles and new recommendations for resistance factors phi qp, phi qs, and phi load were proposed to be 0.65, 0.70, and 0.80, respectively.