Expansive soil is one of the factors that cause road damage in Indonesia. Its behavior is influenced by moisture content. At high moisture content, expansive clay has a very low bearing capacity and high swelling and shrinkage rate compared to other soil types. This soil expansion causes a heave force on the road pavement. When the force exceeds the strength of the pavement, the pavement will deform and break as the initial damage is created. Therefore, it is critical to investigate the effect of moisture content on the swelling-shrinkage behavior of expansive soil. In this study, soil expansion is numerically predicted using the finite element approach on ABAQUS compared to the laboratory expansion index test. The geometric shape and loading of the soil model are the same as the sample shape and loading of a laboratory expansion index test. The Mohr-Coulomb soil constitutive model with sorption is used to simulate water absorption in partially saturated soils. Coupled wetting liquid flow and porous medium stress analysis are used to simulate swelling and shrinkage. The simulation is divided into two types: geostatic, which simulates soil model loading, and coupled pore fluid, which simulates changes in water content. The simulation is then compared to the laboratory test for validation. The numerical analysis results show that the model's accuracy depends highly on the constitutive soil model, whereas the Mohr-Coulomb model shows a limitation in accuracy with the maximum swelling in the simulation is 21.704%, while the average maximum swelling in laboratory testing is 15.515%.

Lateral deformation of group piles foundation is one of the parameters that must be considered properly, excessive lateral deformation can cause damage to the structure. In bridge structures, cases of excessive lateral deformation often occur which potentially affect the reliability of the bridge and cause damage to the structure. When the lateral deformation that occurs in the foundation group exceeds the safety limit, it needs additional reinforcement designed to provide additional lateral resistance, so that the deformation that occurs can be reduced and the strength of the structure also increases. Reinforcement using inclined piles (batter piles) can be used in increasing the lateral resistance of the group piles foundation. The use of batter piles mechanically distributes the horizontal load to the vertical direction of the foundation, so that the lateral load that carried by the foundation is distributed into vertical and horizontal components, to reduce the lateral deformation that occurs. In this study, the lateral deformation analysis was carried out on the group piles foundation on the jetty bridge which experienced a large deformation, then a reinforcement design was designed using batter piles to increase lateral resistance. The analysis was performed using PLAXIS 2D and GROUP software. From the analysis, it was found that reinforcement using batter piles can reduce the lateral deformation that occurs and increase the stability of the bridge..Keywords: batter piles, lateral deformation, lateral resistance

Lateral supports, including walls and bracing systems on deep excavation, are generally required to prevent excessive horizontal wall movement and ground surface settlement which can cause damage to the excavation construction itself and adjacent structures. These criteria are influenced by the stiffness of the excavation system, including the spacing of vertical and horizontal supports (struts). This paper presents the parametric study using the variation of struts spacing in the vertical and horizontal direction to analyze the influence on horizontal wall movement and ground surface settlement. The analysis was carried out using finite element software, PLAXIS performed in 2D plain strain and 3D. This study shows that struts spacing in the horizontal and vertical direction is equally important and equally significant on the deformation that occurs with a maximum difference of about 0.06%. The maximum horizontal wall movement ratio computed by 3D analysis to the 2D analysis is defined as plain strain ratio (PSR). The PSR value decreases when the system stiffness is decreased. Meanwhile, when the system stiffness was higher, the PSR value will be higher and closer to 1, showing that the difference in the 3D and 2D models is relatively small.