671017.pdf

Hindawi Publishing Corporation
Journal of Applied Mathematics
Volume 2013, Article ID 320890, 11 pages
http://dx.doi.org/10.1155/2013/320890

Research Article

Comparative Study on Interface Elements,

Thin-Layer Elements, and Contact Analysis Methods in

the Analysis of High Concrete-Faced Rockfill Dams

Xiao-xiang Qian, Hui-na Yuan, Quan-ming Li, and Bing-yin Zhang

State Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University,

Beijing 100084, China

Correspondence should be addressed to Bing-yin Zhang; [email protected]

Received 3 June 2013; Accepted 15 August 2013

Academic Editor: Pengcheng Fu

Copyright © 2013 Xiao-xiang Qian et al. This is an open access article distributed under the Creative Commons Attribution

License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly

cited.

This paper presents a study on the numerical performance of three contact simulation methods, namely, the interface element,

thin-layer element, and contact analysis methods, through the analysis of the contact behavior between the concrete face slab and

the dam body of a high concrete-faced rockfill dam named Tianshengqiao-I in China. To investigate the accuracy and limitations

of each method, the simulation results are compared in terms of the dam deformation, contact stress along the interface, stresses in

the concrete face slab, and separation of the concrete face slab from the cushion layer. In particular, the predicted dam deformation

and slab separation are compared with the in-situ observation data to classify these methods according to their agreement with the

in-situ observations. It is revealed that the interface element and thin-layer element methods have their limitations in predicting

contact stress, slab separation, and stresses in the concrete face slab if a large slip occurs. The contact analysis method seems to be

the best choice whether the separation is finite or not.

1. Introduction

The cracking of the concrete slab is the most important
factor affecting the safety of concrete-faced rockfill dams
(CFRDs). Accurate computation of stress and deformation in
the concrete slab are key issues for slab cracking assessment.
Numerical methods can be used to predict the deformation
and stress distributions in the concrete face slab, where the
behavior of the interface between the concrete face slab
andthecushionlayerplaysasignificantrole.Becausethe
interface can be treated in different ways, the prediction of
displacement and stress distribution around the interface
may be different. This study focuses on the comparison of
different interface analysis methods through the analysis of
stress and displacement distributions near the interface in the
Tianshengqiao-I CFRD project. The accuracy and limitations
of each method are discussed.
Much attention has been paid to numerical treatment
of the interfaces in geotechnical problems such as buried
structures, jointed rocks, and rockfill dams [ 1 – 5 ]. Interface
behavior often involves large relative movement or even

debonding [ 6 ]. Over the past three decades, three numerical

methods have been proposed for simulating the displace-

ment jump along the interface: the interface element, thin-

layer element, and contact analysis methods. The interface

element method originated from the Goodman joint element

approach [ 2 – 6 ]. The basic idea was to introduce a constitutive

model for an interface of zero thickness [ 6 ]. This consti-

tutive model may be elastic, rigid-plastic, or elastic-plastic

[ 2 , 6 , 7 ]. As an alternative, a thin-layer element method

[ 8 ] was proposed. The thin-layer element method regards

joints or interfaces as conventional continuums described

by solid elements. However, the material modulus for this

thin layer is much lower than that for the intact solid [ 8 –

11 ]. This thin-layer element method has been successfully

applied to jointed rock masses [ 10 ], buried pipes [ 8 ], and the

interaction of foundation and soil masses [ 9 , 11 ]. Either the

interface element or thin-layer element is limited to small

deformation. Different from the previous two numerical

methods, the contact analysis method was proposed to

simulate the contact behaviors between the concrete face