Numerical study of the effects of groundwater drawdown on ground settlement for excavation in residual soils

Abstract

For deep excavations in residual soils that are underlain by highly fissured or fractured rocks, it is common to observe the drawdown of the groundwater table behind the excavation, resulting in seepage-induced ground settlement. In this study, finite element analyses are firstly performed to assess the critical parameters that influence the ground settlement performance in residual soil deposits subjected to groundwater drawdown. The critical parameters that influence the ground settlement performance were identified as the excavation width, the excavation depth, the depth of groundwater drawdown, the thickness of the residual soil, the average SPT N value of the residual soil, the location of the moderately weathered rock, and the wall system stiffness. Subsequently, an artificial neural network (ANN) model was developed to provide estimates of the maximum ground settlement. Validation of the performance of ANN model was carried out using additional data derived from finite element analyses as well as with measured data from a number of excavation sites.

A study of subsidence hotspots by mapping vulnerability indices through innovatory ‘ALPRIFT’ using artificial intelligence at two levels

“…Research on land subsidence is topical in engineering and environmental research, as its impacts are observed in many countries including China, Iran, Japan, Singapore, Thailand and the USA (Ye et al 2015;Nadiri et al 2018a;Hayashi et al 2009;Phien-wej et al 2006;Zhang et al 2018;Goh et al 2019;Galloway et al 1999). Some engineering impacts of subsidence are outlined by Kihm et al (2007), which include the following: (i) a collapse of water wells and the breakage of their casings and ancillary works by compacted soil due to decline of the water table in aquifers; (ii) the requirement for realignment of diversion structures in open channels; (iii) redistribution of stresses and strains in building works and structures creating the potential for excessive forces and subsequent failures.…”

Monitoring Data Analysis and Structural Reliability of Foundation Pit During Construction: A Case Study

“…Although groundwater control measures have been taken, it is observed that the groundwater level behind the side wall will gradually decrease with the increase of excavation depth. Due to the decrease of groundwater level, obvious ground settlement was observed 35 . The increase of ground settlement will increase the soil loss, which will reduce the reliability.…”

Application of Fiber Bragg Grating Sensor Technology to Leak Detection and Monitoring in Diaphragm Wall Joints: A Field Study

“…When a joint in a D-wall does contain defects, leakage may occur. If the excavation is below the groundwater table, there is the possibility that water inrush and piping may occur during excavation, resulting in land subsidence and even disaster [ 6 , 7 , 8 , 9 , 10 ]. Furthermore, the bearing capacity of the foundation will decrease with the inrush of groundwater into the excavation zone [ 11 ].…”