Effect of Soil Spatial Variability on Lateral Response of Well Foundation Embedded in Linear Elastic Soil
01 Jan 2020-pp 429-439
TL;DR: In this article, the effect of soil spatial variability on response of laterally loaded well foundation embedded in linear elastic soil medium is modeled using random field theory and Monte Carlo simulation technique is used to generate various random realization of spatial variability of soil.
Abstract: This paper presents, the effect of soil spatial variability on response of laterally loaded well foundation embedded in linear elastic soil medium. The spatial variation of elastic modulus of soil along embedment depth of the foundation is modeled using random field theory. Elastic modulus of soil is considered to be random variable that follows Log-Normal probability distribution. Monte Carlo simulation technique is used to generate various random realization of spatial variability of elastic modulus of soil. Random realization is done for different values of coefficient of variation of elastic modulus with different spatial correlation distance. A finite element model is developed for laterally loaded well foundation embedded in linear soil. The finite element model is then coupled with the random field of elastic modulus of soil to analyze effect of soil spatial variability on the response of well foundation under different values of lateral load. The results obtained from this study indicate that spatial variation of soil elastic properties has small effect on lateral response of well foundation irrespective of magnitude of lateral load.
TL;DR: In this paper, the force required to rectify the shift and tilt of a reinforced concrete well of 40.8m deep located near the bank of river Gandak in the state of Bihar, India was determined by numerical and analytical method based on finite element simulation and earth pressure theory (conventional method), respectively.
Abstract: Well foundation is a common type of foundation normally used in bridge construction to transfer heavy load from superstructure and moving vehicles. During construction, sinking of well at the site poses a lot of challenges due to several reasons, such as heavy mass of well, properties of soil, location of ground water table and velocity of water in river or canal. During sinking, the well may tilt and shift from its original vertical position and thereby affecting its functionality. In the current investigation, the force required to rectify the shift and tilt of a reinforced concrete well of 40.8 m deep located near the bank of river Gandak in the state of Bihar, India was determined by numerical and analytical method based on finite element simulation and earth pressure theory (conventional method), respectively. The outer and inner diameter of the well was 8.0 m and 4.9 m, respectively. In numerical study, a straight well was built and the force required to shift the well equal to the amount observed at site was determined by trial and error method. In the conventional method, the force required for rectification of the tilt and shift of the well was calculated. For both numerical and analytical study, three different depths of soil layer surrounding the well were considered for the study. By comparing the results of numerical and analytical method, the best possible condition was chosen. The soil condition was further modified, and the required force was calculated by conventional method. Further, kentledge load was applied to investigate its effect on rectification of shift and tilt of well foundation. In conventional method, by removing the top two soil layers and entire depth of soil from the surrounding of well, the inclined force was noted to decease about 79 and 99%, respectively. It was also noted that with 10 MN increase in kentledge load, the inclined force decreased by 0.82 MN. Therefore, the application of inclined force is more effective than the kentledge load for well straightening. Hence, greater effort is required for the restoration of tilt and shift due to the overburden pressure and self-weight of the well after sinking of well to a considerably deeper soil stratum. Therefore, rectifying measures should be taken immediately at the site as soon as tilt and shift is observed.
TL;DR: In this article, the authors used a lognormal distribution and an isotropic correlation structure to estimate the probability of differential settlement under a single spread footing and under a pair of spread footings.
Abstract: By modeling soils as spatially random media, estimates of the reliability of foundations against serviceability limit state failure, in the form of excessive differential settlements, can be made. The soil's property of primary interest is its elastic modulus, E, which is represented here using a lognormal distribution and an isotropic correlation structure. Prediction of settlement below a foundation is then obtained using the finite element method. By generating and analyzing multiple realizations, the statistics and density functions of total and differential settlements are estimated. In this paper probabilistic measures of total settlement under a single spread footing and of differential settlement under a pair of spread footings using a two-dimensional model combined with Monte Carlo simulations are presented. For the cases considered, total settlement is found to be represented well by a lognormal distribution. Probabilities associated with differential settlement are conservatively estimated through the use of a normal distribution with parameters derived from the statistics of local averages of the elastic modulus field under each footing.
TL;DR: Gerolymos et al. as mentioned in this paper developed a generalized spring multi-Winkler model for the static and dynamic response of rigid caisson foundations of circular, square, or rectangular plan, embedded in a homogeneous elastic.
TL;DR: In this article, three probabilistic methods of different complexity for slope stability calculations are evaluated with respect to a well-documented case study of slope failure in Lodalen, Norway.
TL;DR: The use of multidimensional random fields to model real engineering systems is gaining acceptance as personal computer systems become increasingly powerful.
Abstract: The use of multidimensional random fields to model real engineering systems is gaining acceptance as personal computer systems become increasingly powerful. The accuracy of such models depends dire...
TL;DR: In this paper, the authors developed an analytical model that accounts for the multitude of soil resistance mechanisms mobilized at their base and circumference, while retaining the advantages of simplified methodologies for the design of noncritical facilities.