Consolidation assessment using Multi Expression Programming

© 2019 Elsevier B.V. In this study, new approximate solutions for consolidation have been developed in order to hasten the calculations. These solutions include two groups of equations, one can be used to calculate the average degree of consolidation and the other one for computing the time factor (inverse functions). Considering the complicated nature of consolidation, an evolutionary computation technique called Multi-Expression Programming was applied to generate several non-piecewise models which are accurate and straightforward enough for different purposes for calculating the degree of consolidation for each depth and its average as well for the whole soil layer. The parametric study was also performed to investigate the impact of each input parameter on the predicted consolidation degree of developed models for each depth. Moreover, the results of the consolidation test carried out on four different clays attained from the literature showed the proper performance of the proposed models

Cone Penetration Testing 2022

This volume contains the proceedings of the 5th International Symposium on Cone Penetration Testing (CPT’22), held in Bologna, Italy, 8-10 June 2022. More than 500 authors - academics, researchers, practitioners and manufacturers – contributed to the peer-reviewed papers included in this book, which includes three keynote lectures, four invited lectures and 169 technical papers. The contributions provide a full picture of the current knowledge and major trends in CPT research and development, with respect to innovations in instrumentation, latest advances in data interpretation, and emerging fields of CPT application. The paper topics encompass three well-established topic categories typically addressed in CPT events: - Equipment and Procedures - Data Interpretation - Applications. Emphasis is placed on the use of statistical approaches and innovative numerical strategies for CPT data interpretation, liquefaction studies, application of CPT to offshore engineering, comparative studies between CPT and other in-situ tests. Cone Penetration Testing 2022 contains a wealth of information that could be useful for researchers, practitioners and all those working in the broad and dynamic field of cone penetration testing

Nonlinear seismic soil-pile interaction analysis for bridges founded in Quebec soil

This doctorate program focuses on the nonlinear behavior of seismic soil-structure interaction of deep foundations with particular emphasis in Quebec soil. Soil-structure interaction (SSI) plays a crucial role when analyzing and designing important or essential structures, such as skyscrapers, nuclear reactor facilities and highway bridges. For the latter, deep foundations are commonly used to support the bridge superstructure. Historically, the analysis of the interaction between the piles and the embedment soil under lateral loadings used the beam on Winkler theory which is implemented through the p-y curves general method. The commonly-used springs are driven originally from full-scale tests on piles with static or slow cyclic lateral load application. Evidences, from disturbed or damaged structures after earthquake, indicate that SSI follows different curve from the static p-y curve used in the design. The main objective of this research study is to contribute bridge the gap by carrying comprehensive nonlinear seismic analyses on soil-pile interaction for Quebec soils. Extensive numerical investigations have been conducted on 600 parametrical models in order to evaluate these variations and gaps. Results from this research study shows that the following parameters have a direct impact on the seismic soil-pile interaction: the length of the pile, the mass of the structure, as well as the intensity of the seismic record. The seismic soil-pile interaction (SPSI) is normally investigated by dynamic time history analysis on continuum soil-structure models. However, this process is long and time consuming particularly in engineering practice. A new simplified method is proposed in this study to scale the static p-y curves in order to simulate the dynamic behavior of SPSI. The results indicate a reasonable matching between the results from time-history and static analysis. Scaling the current p-y curves in order to simulate the SPSI, would results in a more accurate estimation for the seismic demands on the bridge. Furthermore it will reduce the computation cost by benefiting from currently-used and fast to implement p-y curve method. Field experiments on several types of soil are recommended in order to normalize these findings for engineering practice

A prototype knowledge-based system for pavement analysis

Highway engineers have addressed the problem of pavement maintenance by developing remaining life assessment methods based on structural analysis of computer simulations of pavements tested in the field by non-destructive testing devices such as the Falling Weight Deflectometer (FWD). However the methodologies followed have been shown to be unable to provide accurate solutions without undue reliance on the knowledge of the expert engineer who conducts the analysis. A knowledge-based system (KBS) is proposed to "inject" engineering knowledge into the conventional techniques. It has been established on a systematic basis and seeks to cover the variety of the issues which may be encountered in such systems. In its prototype form the system consists of three parts: 1. The finite element analytical program ROSTRA-1. 2. A deductive database. 3. A back-analysis subsystem. The analytical program carries out the analysis of the pavements tested in the field. The deductive database holds the properties of a variety of paving materials and establishes the analytical model. The back-analysis subsystem seeks to perform the tasks required for the analysis of the FWD deflection bowl. To build this system, the POPLOG-Prolog computer language operated under VAX/VMS was selected to work in connection with the analytical program. An evaluation procedure was carried out to investigate the performance characteristics of the prototype system. The results indicated that the POPLOG-Prolog development environment is not the ideal tool for such an application. In addition, it appears unlikely that there is any other development tool available which is markedly more effective than that used. However it is felt that similar functions to those required by the POPLOG-Prolog environment, may be implemented using conventional programming. To permit this, a logical design of a KBS to conduct this task is presented

Evolutionary and ensemble machine learning predictive models for evaluation of water quality

Study region Bisham Qilla and Doyian stations, Indus River Basin of Pakistan Study focus Water pollution is an international concern that impedes human health, ecological sustainability, and agricultural output. This study focuses on the distinguishing characteristics of an evolutionary and ensemble machine learning (ML) based modeling to provide an in-depth insight of escalating water quality problems. The 360 temporal readings of electric conductivity (EC) and total dissolved solids (TDS) with several input variables are used to establish multi-expression programing (MEP) model and random forest (RF) regression model for the assessment of water quality at Indus River. New hydrological insight for the region The developed models were evaluated using several statistical metrics. The findings reveal that the determination coefficient (R2) in the testing phase (subject to unseen data) for the all the developed models is more than 0.95, indicating the accurateness of the developed models. Furthermore, the error measurements are much lesser with root mean square logarithmic error (RMSLE) nearly equals to zero for each developed model. The mean absolute percent error (MAPE) of MEP models and RF models falls below 10% and 5%, respectively, in all three phases (training, validation and testing). According to the sensitivity study of generated MEP models about the relevance of inputs on the predicted EC and TDS, shows that bi-carbonates and chlorine content have significant influence with a sensitiveness score more than 0.90, whereas the impact of sodium content is less pronounced. All the models (RF and MEP) have lower uncertainty based on the prediction interval coverage probability (PICP) calculated using the quartile regression (QR) approach. The PICP% of each model is greater than 85% in all three stages. Thus, the findings of the study indicate that developing intelligent models for water quality parameter is cost effective and feasible for monitoring and analyzing the Indus River water quality.Web of Science46art. no. 10133

Data Acquisition and Management for Rock Evaluation

The primary goal of this thesis was the formulation of an integrated effort to collect, maintain, exchange, and evaluate engineering data on rock materials from a variety of information sources. The proposed rock evaluation program provides a data base of accumulated information by establishing procedures for characterizing rock, from specimen acquisition through indexing, classification and correlation studies of data, and the application of data for site selection, use tables, establishment of design parameters and alternatives, and maintenance of engineered facilities. The co-ordinated evaluation system detailed herein provides guidelines for implementation of an extensive system of data storage and retrieval to investigate the physico-mechanical aspects of both intact rock samples and in-situ rock masses. The exchange of disciplined information would be to the mutual benefit of practicing engineers and research scientists and would advance the study of rock behavior

Landfill lining engineering designs: a probabilistic approach

Uncertainty and variability are prevalent in any engineering design. In this study, the uncertainty of input parameters for the stability of a landfill veneer cover soil and the integrity of a lining system were treated probabilistically using Monte Carlo simulation. Statistical information required to postulate the distribution types of input parameters, taken as random variables, were identified and characterised using available data from literature survey and a designed laboratory repeatability testing programme. The variability and uncertainty of interface shear strengths (τ) and the derived strength parameters for three generic interfaces, commonly found in a landfill lining system, were computed and compared using these types of information. The variability of τ computed using the combined global database were three-to-five times and could reach up to seven times higher for the derived strength parameters when compared to laboratory repeatability test results. Additionally, a normal distribution was recommended for interface shear strengths and derived parameters (except interface adhesion with high COV) for good quality data based on subjective and objective statistical test methods. [Continues.

Lateral Capacity of Piles and Caissons in Cohesive Soils

Upper bound plastic limit analysis (PLA) solutions have been widely used to assess maximum capacity of laterally loaded piles and caissons. However, for the specific case of short piles and caissons with aspect ratios generally ranging from one to three, the current solutions tend to over-estimate capacities. Furthermore, these over predictions seem to be significantly influenced by eccentricity of loading. This dissertation presents a unified upper bound plastic limit analysis solution aiming to improve predictions of capacity for the aforementioned cases. In addition, a simplified upper bound method is proposed for cases in which computational efficiency is needed. Both solutions are compared to results from three dimensional finite element studies. Towards this end, most of the existing simplified predictive methods typically apply to idealized soil strength profiles that are either constant or linearly increasing with depth. However, site investigations often reveal complex strength profiles that deviate significantly from simple linear profiles. One example is the case in which a superficial stiff layer overlays a thicker layer of very soft soil. The work herein presented also includes analyses of pile and caisson performance in stratified soils based on a three dimensional upper bound PLA with a collapse mechanism comprising a surface failure wedge, a flow-around region and a spherical base failure surface. An introductory discussion on the influence of soil stratigraphy and geology for design purposes is included. Selected strength distributions are representative from field data obtained through cone penetration testing. Finally, the installation of driven piles and suction caissons in clayey soils generates excess pore pressures that temporarily reduce load capacity due to side resistance. Time dependent dissipation of these excess pore pressures leads to recovery of side resistance, a process known as ‘setup’. Since many facilities cannot be put into operation until sufficient pile load capacity has been mobilized, realistic predictions of setup time can be important. A simplified method of analysis for calculation of the setup time following open ended pile penetration is also presented

Lateral Capacity of Piles and Caissons in Cohesive Soils

Upper bound plastic limit analysis (PLA) solutions have been widely used to assess maximum capacity of laterally loaded piles and caissons. However, for the specific case of short piles and caissons with aspect ratios generally ranging from one to three, the current solutions tend to over-estimate capacities. Furthermore, these over predictions seem to be significantly influenced by eccentricity of loading. This dissertation presents a unified upper bound plastic limit analysis solution aiming to improve predictions of capacity for the aforementioned cases. In addition, a simplified upper bound method is proposed for cases in which computational efficiency is needed. Both solutions are compared to results from three dimensional finite element studies. Towards this end, most of the existing simplified predictive methods typically apply to idealized soil strength profiles that are either constant or linearly increasing with depth. However, site investigations often reveal complex strength profiles that deviate significantly from simple linear profiles. One example is the case in which a superficial stiff layer overlays a thicker layer of very soft soil. The work herein presented also includes analyses of pile and caisson performance in stratified soils based on a three dimensional upper bound PLA with a collapse mechanism comprising a surface failure wedge, a flow-around region and a spherical base failure surface. An introductory discussion on the influence of soil stratigraphy and geology for design purposes is included. Selected strength distributions are representative from field data obtained through cone penetration testing. Finally, the installation of driven piles and suction caissons in clayey soils generates excess pore pressures that temporarily reduce load capacity due to side resistance. Time dependent dissipation of these excess pore pressures leads to recovery of side resistance, a process known as ‘setup’. Since many facilities cannot be put into operation until sufficient pile load capacity has been mobilized, realistic predictions of setup time can be important. A simplified method of analysis for calculation of the setup time following open ended pile penetration is also presented

Structure-Seabed Interactions in Marine Environments

The phenomenon of soil–structure interactions in marine environments has attracted great attention from coastal geotechnical engineers in recent years. One of the reasons for the growing interest is the rapid development of marine resources (such as in the oil and gas industry, marine renewable energy, and fish farming industry) as well as the damage to marine infrastructure that has occurred in the last two decades. To assist practical engineers in the design and planning of coastal geotechnical projects, a better understanding of the mechanisms of soil–structure interactions in marine environments is desired. This Special Issue reports the recent advances in the problems of structure–seabed interactions in marine environment and provides practical engineers and researchers with information on recent developments in this field