In performance-based design, it is crucial to understand deformation characteristics of geocell layers in soil under footing loads. To explore this, a series of laboratory loading tests were carried out to investigate the influence of varying parameters on the strain levels within the geocell layer in a sandy soil under axial strip footing loading. The results were analyzed in terms of maximum strain levels, strain variation along the geocell layer and the correlation between horizontal and vertical strains. In this study, the maximum observed strain levels for geocellreinforced strip footing systems reached 2.3 % for horizontal (tensile) strain and 1.4 % for vertical (compressive) strain. Furthermore, most strain levels were concentrated within a distance of 1.5 times the footing width from the axis of strip footing. In geocell-reinforced footing systems, the interaction between horizontal and vertical strains becomes a key factor, with the ratio of horizontal to vertical cell wall strains ranging approximately from 1 to 2.5. The outcomes of this study are expected to contribute to the practical applications of geocell-reinforced footing systems.

The faster growth of urban areas, coupled with limited available land, has resulted in the development of densely packed buildings sharing common soil media. This proximity increases soil stress, influencing the deformation characteristics of nearby footings. Hence, there is a need to investigate the effect of structure-soil-structure interaction (SSSI) on the footing settlement. The aim of the study is to investigate the effect of SSSI on the footing settlement of a three-story symmetrical RCC building due to the presence of adjacent building with various height. The vertical and differential settlement of footings obtained from SSSI and soil-structure interaction (SSI) analyses are compared by using the finite element software ANSYS under gravity loading. The findings reveal that SSSI substantially amplifies vertical settlement in footings proximate to adjacent structures compared to SSI analysis, consequently inducing significant changes in differential settlement patterns between footings.

Rapid urbanization and land scarcity lead to the construction of multiple structures in proximity, supported on common soil media. This proximity increases soil stress, influencing the deformation characteristics of nearby footings. Hence, there is a need to investigate the effect of structure-soil-structure interaction (SSSI) on the footing settlement. In the present study, the effect of SSSI on the footing settlement of a three-storey building is investigated due to the presence of similar adjacent buildings arranged in various patterns (single adjacent building, side-by-side, L-shape, and inverted T-shape). The various interaction analyses are performed using finite element software ANSYS under gravity loading. The vertical and differential settlement of footings obtained from soil-structure interaction (SSI) and SSSI analyses are compared to evaluate the effect of SSSI under various adjacent building arrangements. The results indicate that in SSI case, inner footings show greater settlement compared to peripheral footings which causes high value of differential settlement between peripheral footings and those immediately adjacent to them. However, the presence of an adjacent structure in SSSI cases provides higher settlement in adjacent footings, which in turn reduces the differential settlement in these footings. Moreover, the SSSI effect on vertical settlement in SSSI (L-shaped) and SSSI (inverted T-shaped) is found to be more in corner footing located near to the adjacent buildings due to overlapping of soil stresses from two sides. The study quantifies the extent of settlement increase in various SSSI cases compared to SSI case, contributing valuable insights to mitigating potential settlement issues in densely developed areas.

The growing global issue of waste tyres, which are non-biodegradable, poses serious environmental risks, with improper disposal and burning contributing to air and water pollution through the release of harmful chemicals and greenhouse gases. However, waste tyres possess unique engineering properties such as high tensile strength, permeability, durability, fatigue resistance, resilience, and flexibility. This study explores the potential of utilizing waste tyres to enhance soil strength through experimental investigations. Laboratory model tests were conducted on circular footing (150 mm diameter) placed on various foundation systems, considering sand or sand-tyre shred mattress overlying a soft clay bed (Cu = 14.5 kPa), with and without geogrid reinforcement at the interface of soft clay and sand-tyre. Results revealed that the maximum improvement in bearing capacity of the foundation systems, with or without geogrid, was observed at a thickness of sand layer (hs) or sand-tyre mixture (hSTM) = 1.5D, over the soft clay. Results also revealed that with the inclusion of tyre shreds (7.5% by volume) with sand, over the soft clay bed, the bearing pressure of foundation system S-IV increased by 200.01% (at hsTM = 1.5D) in comparison with S-I. This improvement in bearing capacity of S-IV (i.e. clay + sand + tyre) was 3.5 times than S-I, which is similar to the improvement in bearing capacity of foundation system S-III (i.e. clay + geogrid + sand). Based on the experimental evidence, it can be suggested that the application of tyre shred is beneficial in geotechnical engineering practices to improve the performance of soft clay foundation systems.

A series of physical model tests and cyclic triaxial tests were performed on a dry sand to investigate the effects of excavating an adjacent pit on the settlement behaviour of a footing under cyclic loading. The excavation is simulated by moving a retaining wall between loading cycles in the physical model tests. The excavation induced stress disturbance on soil elements is modelled by reducing cell pressure between loading cycles in triaxial tests. The results indicate that nearby excavation leads to reduction in lateral stress in ground and therefore increases the settlement of footing in the subsequent loading cycles. However, there is no clear relationship between the settlement increment and the magnitude of wall movement, when the lateral movement of the wall is within the range of 0.1% to 0.37% of the wall height. The lateral excavation does not have great impact on the influence zone of the footings under cyclic loading. An empirical model is proposed to estimate the cyclic loading-induced strain accumulation of sand with the consideration of lateral unloading effects between loading cycles. After being validated using cyclic triaxial tests results, the proposed model is employed to predict cyclic loading-induced settlement of the footing before and after the excavation.