Pile response due to unsupported excavation-induced lateral soil movement

1996 ◽  
Vol 33 (4) ◽  
pp. 670-677 ◽  
Author(s):  
H G Poulos ◽  
L T Chen
Keyword(s):  
Finite Element ◽  
Boundary Element ◽  
Bending Moment ◽  
Major Effect ◽  
Soil Movement ◽  
Lateral Soil Movement ◽  
Clay Layers ◽  
Stage Analysis ◽  
Pile Response ◽  
Element Method

In this paper, a two-stage analysis involving the finite element method and the boundary element method is used to study pile response due to excavtion-induced lateral soil movements, focusing on unsupported excavations in clay layers. It is shown that the pile response in this case is different from that caused by excavations which are braced. Design charts for estimating pile bending moments and deflections are presented for free-head single piles, and these may be used in practice for assessing the behaviour of existing piles due to the excavation. However, proper account should be taken of the pile head condition, which has been found to have a major effect on the pile bending moment. The application of the charts is demonstrated via a study of a published case history. Comparisons are presented between measured pile behaviour and that predicted both from the chart solutions and the computer analyses, and reasonably good agreement is found between them. Key words: analysis, boundary element, excavation, finite element, pile, soil, movement.

Effect of consolidation on responses of a single pile subjected to lateral soil movement

2015 ◽  
Vol 52 (6) ◽  
pp. 769-782 ◽  
Author(s):  
L.Z. Wang ◽  
K.X. Chen ◽  
Y. Hong ◽  
C.W.W. Ng
Keyword(s):  
Soft Clay ◽  
Bending Moment ◽  
Coefficient Of Consolidation ◽  
Construction Period ◽  
Soil Movement ◽  
Centrifuge Tests ◽  
Short Period ◽  
Lateral Soil Movement ◽  
Pile Response ◽  
Pile Length

Given extensive research carried out to study pile response subjected to lateral soil movement in clay, the effect of consolidation on the pile–soil interaction is rarely considered and systematically investigated. For this reason, four centrifuge tests were conducted to simulate construction of embankment adjacent to existing single piles in soft clay, considering two typical drainage conditions (i.e., drained and undrained conditions) and two typical pile lengths (i.e., relatively long pile and short pile). The centrifuge tests were then back-analyzed by three-dimensional coupled-consolidation finite element analyses. Based on reasonable agreements between the two, numerical parametric studies were conducted to systematically investigate and quantify the influence of construction rate and pile length on pile response. It is revealed that by varying drainage conditions, the piles respond distinctively. When the embankment is completed within a relatively short period (cvt/d2 < 2, where cv, t, and d denote the coefficient of consolidation, construction period, and pile diameter, respectively), the pile located adjacent to it deforms laterally away from the embankment. Induced lateral pile deflection (δ) and bending moment reduce with construction period. On the contrary, embankment constructed within a relatively long period (cvt/d2 > 200) leads the pile to deform laterally towards the embankment, with δ and bending moment increases with construction period. By halving the length of pile embedded in the drained ground, the maximum induced bending moment (BMmax) was slightly reduced (by 23%). On the other hand, shortening the length of the pile in the undrained ground is much more effective in reducing BMmax, i.e., halving pile length resulting in 78% reduction in bending moment. A new calculation chart, which takes various drainage conditions and pile lengths into account, was developed for estimation of BMmax.

Application of the Boundary Element Method and Modal Analysis to Tire Acoustics Problems

1993 ◽  
Vol 21 (2) ◽  
pp. 66-90 ◽  
Author(s):  
Y. Nakajima ◽  
Y. Inoue ◽  
H. Ogawa
Keyword(s):  
Finite Element ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Acoustic Radiation ◽  
Traffic Noise ◽  
Noise Prediction ◽  
Prediction System ◽  
Tire Noise ◽  
Acoustic Contribution ◽  
Element Method

Abstract Road traffic noise needs to be reduced, because traffic volume is increasing every year. The noise generated from a tire is becoming one of the dominant sources in the total traffic noise because the engine noise is constantly being reduced by the vehicle manufacturers. Although the acoustic intensity measurement technology has been enhanced by the recent developments in digital measurement techniques, repetitive measurements are necessary to find effective ways for noise control. Hence, a simulation method to predict generated noise is required to replace the time-consuming experiments. The boundary element method (BEM) is applied to predict the acoustic radiation caused by the vibration of a tire sidewall and a tire noise prediction system is developed. The BEM requires the geometry and the modal characteristics of a tire which are provided by an experiment or the finite element method (FEM). Since the finite element procedure is applied to the prediction of modal characteristics in a tire noise prediction system, the acoustic pressure can be predicted without any measurements. Furthermore, the acoustic contribution analysis obtained from the post-processing of the predicted results is very helpful to know where and how the design change affects the acoustic radiation. The predictability of this system is verified by measurements and the acoustic contribution analysis is applied to tire noise control.

Postbuckling Analysis of Plates Under Combined Loads by a Mixed Finite Element and Boundary Element Method

1993 ◽  
Vol 115 (3) ◽  
pp. 262-267 ◽  
Author(s):  
J. Q. Ye
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Mixed Boundary ◽  
Mixed Finite Element ◽  
Plane Deformation ◽  
Thin Plates ◽  
Combined Loads ◽  
Element Method

The postbuckling behavior of thin plates under combined loads is studied in this paper by using a mixed boundary element and finite element method. The transverse and the in-plane deformation of the plates are analyzed by the boundary element method and the finite element method, respectively. Spline functions were used as the interpolation functions and shape functions in the solution of both methods. A quadratic rectangular spline element is adopted in the finite element procedure. Numerical results are given for typical problems to show the effectiveness of the proposed approach. The possibilities to extend the method developed in this paper to more complicated postbuckling problems are discussed in the concluding section.

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