Abstract: Due to the rigid deformation limit of high-speed railways, the anti-frost heave design has become a critical concern in seasonally frozen regions. In this study, the authors explained the frost heave mitigation techniques adopted for the high-speed railway between Harbin and Dalian in northeast China and then presented the thermal, deformation, and water content data monitored on the Gongzhuling test site. According to these data, the authors proposed the possible frost heave mechanisms of the high-speed railway foundation. The foundation is composed of well-graded gravel with cement and A/B group fill, which are treated as non-frost-susceptible materials in general. Based on the monitored data, the authors found that the surface layer (0–0.5 m) contributed most to the total frost heave and this might be caused by local water accumulation inside the foundation (0.6–1.2 m). In order to demonstrate the frost heave ability of these “non-frost-susceptible” materials, the authors conducted an indoor frost heave test with a mixture of gravel and 3% Kaolinite clay. Through this experiment, it was demonstrated that, with sufficient water supply, gravel with a limited amount of fine material can produce significant frost heave. Accordingly, we can conclude that the accumulated water inside high-speed railway foundation causes the frost heave deformation. Therefore, the treatment of the water accumulation within the fills needs to be considered for frost heave elimination or prevention.

Abstract: In general, the blast-induced ground shock excites the foundation of the structure prior to the air-blast pressure because of the obvious reasons of difference in wave propagation velocities. Howev...

Abstract: The present study proposes a finite-element approach to focus on the load sharing and deformation aspects of combined pile–raft foundation (CPRF) in a serviceability-based framework. Soil n...

Abstract: Although the random heterogeneity of a clayey seabed has been long recognised, it is relatively recently that the influence of spatial variability on the spudcan foundation has been explicitly expl...

Abstract: Helical piles are used mainly to resist tension forces generated by uplift and overturning moments of various structures, therefore they have been suggested as a potential alternative to driven pil...

Abstract: The performance of many algorithms in the fields of hard combinatorial problem solving, machine learning or AI in general depends on parameter tuning. Automated methods have been proposed to alleviate users from the tedious and error-prone task of manually searching for performance-optimized configurations across a set of problem instances. However, there is still a lot of untapped potential through adjusting an algorithm’s parameters online since different parameter values can be optimal at different stages of the algorithm. Prior work showed that reinforcement learning is an effective approach to learn policies for online adjustments of algorithm parameters in a data-driven way. We extend that approach by formulating the resulting dynamic algorithm configuration as a contextual MDP, such that RL not only learns a policy for a single instance, but across a set of instances. To lay the foundation for studying dynamic algorithm configuration with RL in a controlled setting, we propose white-box benchmarks covering major aspects that make dynamic algorithm configuration a hard problem in practice and study the performance of various types of configuration strategies for them. On these white-box benchmarks, we show that (i) RL is a robust candidate for learning configuration policies, outperforming standard parameter optimization approaches, such as classical algorithm configuration; (ii) based on function approximation, RL agents can learn to generalize to new types of instances; and (iii) self-paced learning can substantially improve the performance by selecting a useful sequence of training instances automatically.

Abstract: Interface friction is a governing parameter in the performance of piled foundations and other applications. Piles and other foundation elements typically mobilize a similar interface fricti...

Abstract: The intent of this paper is to establish the foundation for improvement of monitoring strategies for the safe and controlled management of the geotechnical stability of a tailings storage f...

Abstract: One of the most prevalent causes of bridge failure around the world is scour, the gradual erosion of soil around a bridge foundation due to fast-flowing water. A reliable technique for monitoring scour would help bridge engineers take timely countermeasures to safeguard against failure. Although vibration-based techniques for monitoring structural damage have had limited success, primarily due to insufficient sensitivity, these have tended to focus on the detection of local damage. High natural frequency sensitivity has recently been reported for scour damage. Previous experiments to investigate this have been limited as a result of the cost of full-scale testing and the fact that scaled-down soil structure models tested outside a centrifuge do not adequately simulate full-scale behaviour. This paper describes the development of what is believed to be the first-ever centrifuge-testing programme to establish the sensitivity of bridge natural frequency to scour. For the fundamental mode of vibration, these tests found up to a 40% variation in natural frequency for 30% loss of embedment. Models of three other types of foundation, which represent a shallow pad foundation, a deep pile bent and a deep monopile, were also tested in the centrifuge at different scour levels. The shallow foundation model showed lower frequency sensitivity to scour than the deep foundation models. The level of frequency sensitivity (3.1 to 44% per scour depth equivalent to 30% of embedment of scour) detected in this experiment demonstrates the potential for using natural frequency as an indicator of both local and global scour of bridges, particularly those with deep foundations.

Abstract: Large-scale simulations and forensic analyses of the seismic behaviour of real case studies are often based on simplified analytical approaches to estimate the reduction in fundamental frequency and the amount of radiation damping induced by dynamic soil-foundation-structure (SFS) interaction. The accuracy of existing closed-form solutions may be limited because they were derived through single degree-of-freedom structural models with shallow rigid foundations placed on a homogeneous, linear elastic half-space. This paper investigates the effectiveness of those formulations in capturing the dynamic out-of-plane response of single load-bearing walls within unreinforced masonry buildings having either a shallow foundation or an underground storey embedded in layered soil. To that aim, analytical predictions based on the replacement oscillator approach are compared to results of two-dimensional dynamic analyses of coupled SFS elastic models under varying geotechnical and structural properties such as the soil stratigraphy, foundation depth and number of building storeys. Regression models and a relative soil-structure stiffness parameter are proposed to quickly predict the frequency reduction induced by SFS interaction, accounting for the presence of an embedded foundation, an underground storey and a layered soil. The effects of SFS interaction are also evaluated in terms of equivalent damping ratio, showing the limitations of simplified approaches. Since the geometric layouts considered in this study are rather recurrent in the Italian and European built heritage, the proposed procedure can be extended to similar structural configurations.

Abstract: The effect of NBA on the durability of the hydraulically bound cemented lateritic soil was investigated and results were observed. Preliminary tests conducted showed that the natural soil was an A-...

Abstract: Buildings constructed adjacent to the slope crest in seismically active areas might be exposed to serious danger when they are subjected to strong earthquake excitations. The ground conditi...

Abstract: Application of bio-inspired design in geotechnical engineering shows promise for improving the energy and material efficiency of several processes in infrastructure construction and site characterization. This project examines tree root systems for use in future bio-inspired design to improve the capacity of foundations used to support, for example, buildings and bridges. Foundation and anchorage elements used in industry are comprised almost solely of linear elements with a constant cross-sectional geometry. This functional form has remained the same for more than a century, primarily due to material availability and installation simplicity. Knowledge and understanding of the mechanisms that contribute to capacity development of natural nonlinear or branched foundation systems, such as tree root systems, could make foundation design more sustainable. The experiments described herein show that the root systems studied are 6-10 times as efficient as a conventional micropile system in developing tensile capacity on a per volume basis, with some systems displaying nearly 100 times efficiency in comparison to a conventional shallow footings. This paper explores the relationship between root system architecture and force-displacement behavior of tree root systems to better understand how to improve foundation capacity and demonstrates the potential for a more efficient use of materials and energy as compared to conventional pile and footing approaches.

Abstract: The piled-raft foundation in soft clay ground for high-speed trains has suffered serious settlement due to cyclic train loading in recent years. It was urgent to implement countermeasures to improve the natural ground. In this research, firstly, a ground treatment technique was proposed to reduce permanent train-induced deformation. Permeation grouting was injected into the bearing strata of group piles with constant pressure. Then numerical simulations based on sophisticated constitutive model and soil–water coupled finite element-finite difference (FE)-(FD) compound arithmetic, were carried out to explore the mitigation effect of the proposed technique. The employed numerical method was validated by using the in-situ monitoring data of lateral ground displacement and surface settlement. The calculation results indicated that reinforcement in the bearing strata of group piles could efficiently increase the tip resistance of piled-raft foundation. Consequently, the surface settlement and sectional forces of group piles can be reduced to a large extent. The proposed ground treatment method was useful for reinforcing pile-raft-soft soil system and had great potential to be applied in practical situations.

Abstract: Seismic settlement of shallow foundations constructed in seismic active areas should be considered for a reasonable estimation of the total settlement. However, the trend of the seismic settlement of shallow foundation constructed on a sandy soil is not clearly understood and it is estimated by designer using simple analytical methods. These methods do not consider the effect of the soil–structure interaction. This research, therefore, reports the results of 105 robust finite element models developed to investigate the seismic settlement of a shallow foundation constructed on a dry sand. The influence of the load applied on the foundation, relative density of sand, foundation embedment, peak ground acceleration of the earthquake shake, thickness of the sandy soil, and the dominant frequency of the earthquake shake have been examined to provide a comprehensive understanding of the parameters influencing the seismic settlement. The results of the analyses showed that increasing the load applied on the foundation or the peak ground acceleration remarkably increases the seismic settlement, while increasing the embedment depth remarkably reduces the seismic settlement. In addition, the relationship between the thickness of the sandy layer and the seismic settlement is found to be very complex and noticeably influenced by the relative density of the sand. More importantly, it was found that the seismic settlement dramatically increases when the dominant frequency of the earthquake approaches the natural frequency of the system. Thus, all these parameters are important and should be considered by designers for a reasonable estimation of the seismic settlement. The conclusions drawn from this paper will aid the development of a good analytical method in future, and the results reported in this paper also provide useful and novel database to designers and practitioners.