Numerical and artificial neural network analyses of ground surface settlement of tunnel in saturated soil
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Numerical and artificial neural network analyses of ground surface settlement of tunnel in saturated soil Vahed Ghiasi1 · Mehdi Koushki2 Received: 18 January 2020 / Accepted: 10 April 2020 / Published online: 20 April 2020 © Springer Nature Switzerland AG 2020
Abstract The main purpose of this research is to predict the ground surface settlement in tunneling of a single circular tunnel with simultaneous changes in the mechanical properties of soil and geometrical properties of the tunnel section. In this research, numerical and parametric analysis of circular tunneling in frictional–cohesive saturated soil has been investigated using 2D finite element method by ABAQUS. In other words, the behavior of ground surface, considering to change the different values of depth-to-diameter ratio (H/D), soil cohesion, internal friction angle, permeability coefficient, and the influence of these variables on settlement of surface in each model, has been separately evaluated. Then, a multilayer perceptron (MLP) artificial neural network is designed to predict the ground surface settlement. MLP is a type of feedforward artificial neural network utilizing backpropagation technique for training phase, and the Levenberg–Marquardt method is used to reduce the errors and the distance between the network outputs and finite element method results. There are some independent variables in the input layer and a dependent variable in the output layer. The middle layer consists of seven neurons. Finally, the high potential of the artificial neural network with a correlation coefficient of 0.98 is shown in the prediction of ground surface settlement. Keywords Ground surface settlement · Finite element method · Multilayer perception artificial neural network
1 Introduction In recent years, there has been an increasing interest in the tunnel construction [1–4]. Ground surface settlement due to tunneling is one of the inevitable problems in tunnel engineering. The long-term settlement and differential settlement of tunnels have led to serious longitudinal deformation. The deformation pattern of tunnels is the step between rings rather than by the beam/cylindrical shell bending. Most of the lining rings distort into the shape of a horizontal ellipse (tunnel squat), but a few acquire the shape of a vertical ellipse. Large tunnel deformation has caused groundwater infiltration and the separation of ballastless track bed and lining. Further analysis shows that long-term tunnel settlement is mainly due to urbanization
induced land settlements in Shanghai. The magnitude of tunnel settlement is correlated with sublayer settlement rather than ground surface settlement. In the early operational years, post-construction settlement induced by tunneling and the cyclic loading of trains may contribute significantly to the tunnel settlement. However, at some special places, nearby construction and groundwater infiltration are responsible for the long-term settlement of the tunnel [5]. In the past few decades, as a new tool for analysis of the tough geot
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