Proceedings of DFI-India 2017: 7th Conference on Deep Foundation Technologies for Infrastructure Development in India, (DFI)
Numerical Modelling of a Deep Excavation Shoring for Replacement of Control Structure at a Dam
Deep K. Khatri, Ph.D., P.E., Staff Geotechnical Engineer, Lok M. Sharma, P.E., Senior Principal and Brett Bradfield, P.E., Senior Project Engineer
A shored enclosure was required to access a control structure upstream below the dam of a deep lake. The shoring involves the interaction of the structure, soil, and water and the loads imposed include the hydrostatic forces of the water, soil pressures as well as dynamic forces due to currents and waves. Deep excavation support systems have traditionally been designed using classical methods that involve direct computations of earth pressures. However, traditional analysis does not take into account soil-structure interaction. Numerical modelling offers better means to analyze soil-structure interaction. This paper presents a 2D finite element (2D-FE) analysis of a deep excavation support structure that was required to remove and replace a control structure at the upstream toe of a dam. The sheet-piling shoring was designed to withstand the lateral pressures from 14 m deep free water and 5.5 m deep excavation below the free water to reach the required excavation level to replace the gate structure. Elastic-plastic analyses were performed to predict the stresses and deformations of the complicated shoring structure and excavation bottom. The soil parameters, procedures used to develop the 2D-FE model, and the results are discussed in this paper. The shoring system is currently under construction.
|article #2742; publication #1035 (India2017)|