COMPLAS 2021 is the 16th conference of the COMPLAS Series.
The COMPLAS conferences started in 1987 and since then have become established events in the field of computational plasticity and related topics. The first fifteen conferences in the COMPLAS series were all held in the city of Barcelona (Spain) and were very successful from the scientific, engineering and social points of view. We intend to make the 16th edition of the conferenceanother successful edition of the COMPLAS meetings.
The objectives of COMPLAS 2021 are to address both the theoretical bases for the solution of nonlinear solid mechanics problems, involving plasticity and other material nonlinearities, and the numerical algorithms necessary for efficient and robust computer implementation. COMPLAS 2021 aims to act as a forum for practitioners in the nonlinear structural mechanics field to discuss recent advances and identify future research directions.
Scope
COMPLAS 2021 is the 16th conference of the COMPLAS Series.
In August 2021, landslides occurred on the slope of the Cortinas sector over an area of more than three kilometers, which affected electrical towers, a national vehicle highway, an oil pipeline and a gas pipeline. Currently, these infrastructures have limitations in their operation, generating significant economic losses and therefore, in the case of the gas pipeline, the construction of a HDD of two thousand meters in length at depths of up to one hundred meters is proposed, with the purpose of being able to bypass the zones unstable and restore transportation to normal conditions. The design and construction of said work constitutes a challenge, since the project area has very special geological conditions, since the hillside deposits are very susceptible to failure and there is apparently a stress tensor of an active fault that directly affects the stability of the area. The projected HDD crosses a ravine and a slope with steep topography with difficult access, as well as different layers of sedimentary rock with intercalations, which are folded and highly fractured and saturated with water. These special conditions generated difficulties and opposed the completion of several attempts by other HDDs, but taking into account that this alternative constitutes basically the only solution from a technical point of view, it was necessary to carry out some borehole and multiple seismic geophysical tests and geoelectrical that would allow defining a detailed stratigraphic profile to be able to analyze the constructive feasibility and, in such case, the most appropriate method, as well as the geomechanically characterization of the rocks, since according to the numerical modeling they indicate that the stability of the drilling may be affected due to plasticization at its limits, with detachments of rock fragments and jamming of the tools necessary for its construction.
Abstract In August 2021, landslides occurred on the slope of the Cortinas sector over an area of more than three kilometers, which affected electrical towers, a national vehicle highway, [...]
The Cañaveral shopping center is located on a low slope formed by recent alluvial deposits of low consistency, supported on sedimentary rock of the Girón formation, which is found at depths that change abruptly between one and twelve meters in short distances, influenced by the presence of a geological fault line and processes of erosion and weathering by subway water currents. Considering that the loads on the foundation are of great magnitude, it is necessary to build about 100 deep caisson foundations to reach the rock. However, performing a borehole on each one of them represented a very high cost and long execution times that would generate discomfort in the operation of the warehouse. Therefore, an alternative was proposed to determine the depth levels of the rock through different geophysical tests of seismic lines and electrical tomography and try to calibrate the results through the correlation of some boreholes. During the execution and data processing phase of the geophysical tests, difficulties were encountered due to the level of environmental noise and the obtaining of the wave records, given the variability of the rock levels and even the effect that in some sectors of the study area the rock is very sub-surface. In conclusion, it was possible to identify the strengths and weaknesses of each of the exploration methods and generate a 3D map of the depths of the rock levels that served as input for the design and budget of the foundations, which were verified by constant supervision during construction and thus be able to determine the error percentages, as well as to present recommendations for future works where it is intended to use this type of techniques
Abstract The Cañaveral shopping center is located on a low slope formed by recent alluvial deposits of low consistency, supported on sedimentary rock of the Girón formation, which [...]
O. Zinas, I. Papaioannou, R. Schneider, P. Cuéllar
ISC2024.
Abstract
Quantifying uncertainties in subsurface properties and stratigraphy can lead to better understanding of the ground conditions and enhance the design and assessment of geotechnical structures. Several studies have utilized Cone Penetration Test (CPT) data and employed Bayesian and Machine Learning methods to quantify the geological uncertainty, based on the Robertson’s soil classification charts and the Soil Behaviour Type Index (Ic). The incorporation of borehole data can reduce the stratigraphic uncertainty. Significant challenges can arise, however, mainly due to the intrinsic differences between field and laboratory-based soil classification systems, which can potentially lead to inconsistent soil classification. To this end, this study proposes a multivariate Gaussian Process model that utilizes site-specific data and: i) jointly models multiple categorical (USCS labels) and continuous (Ic) variables, ii) learns a (shared) spatial correlation structure and the betweenoutputs covariance, and iii) produces two types of dependent classification outputs. The results indicate that the integration of geotechnical and geological information into a unified model can provide more reliable predictions of the subsurface stratification, by allowing simultaneous interpretation of USCS and Ic profiles. Importantly, the model demonstrates the potential to integrate multiple variables of different types, aiming to contribute to the development of a methodology for joint modeling of geotechnical, geological and geophysical data.
Abstract Quantifying uncertainties in subsurface properties and stratigraphy can lead to better understanding of the ground conditions and enhance the design and assessment of geotechnical [...]
One of the most significant processes in soil dynamics is liquefaction. It is a loss of strength coupled by a quick increase in pore pressure, causing soil particles to break apart for a brief period. There have been several approaches published for calculating the residual or liquefied shear strength of cohesionless soils. This article gives cone penetration test relationships for assessing vulnerability to loss of strength and liquefied shear strength in a variety of soils. Then, based on the results of our studies, we were able to map the liquefiable zones of the Mnasra region, located in the Gharb basin and extending over an area of 4000 km2, which is characterized by two main facies: (i) a predominantly gravelly and/or conglomeratic facies, separated by silt-clay levels (east of the nappe), (ii) a predominantly sandy, sandstone and calcareous facies, separated by silt-clay levels (coastal zone and southern sector on the Maâmora side). IPL calculations predict a spatial-temporal variation in liquefaction at depths ranging from a low probability of liquefaction to a certainty
Abstract One of the most significant processes in soil dynamics is liquefaction. It is a loss of strength coupled by a quick increase in pore pressure, causing soil particles to break [...]
Geosynthetics-reinforced soil (GRS) walls have gained immense popularity among other reinforced soil walls. In recent times, case studies have highlighted several GRS walls facing problems such as cracking on the facia, breakage of connection pins in the segmental block, breakage of connection between facia and reinforcement, and relative settlement between facia and backfill, all leading to the serviceability issues or failure of the wall. The existing design methods estimate connection loads using laboratory pull-out tests, which do not incorporate the effect of on-site conditions, such as differential settlement, compaction-induced stresses, and facia geometry, and the stress mobilization in the connection system. This study examines the stress distribution in the facia connection system of segmental reinforced soil walls subjected to site conditions such as inadequate backfill compaction and differential settlement between facia and backfill. A finite element (FE) approach has been adopted to predict the stresses in the reinforcement for the connection loads in the reinforcement-facia connection system subjected to the above-mentioned conditions. The modular block facia, along with geogrid reinforcement connections, was studied, incorporating appropriate geometrical and interface properties (viz. geosynthetics-block interfaces). Based on the study, the obtained variation in the von Mises stresses in the geogrid, embedded in the modular block, due to connection load at the service state was analysed. A comparative analysis of the performance of three different segmental block facia-reinforcement connections was also performed to understand their suitability in a particular site condition
Abstract Geosynthetics-reinforced soil (GRS) walls have gained immense popularity among other reinforced soil walls. In recent times, case studies have highlighted several GRS walls [...]
Based on Cone penetration tests (CPT) data, a number of soil’s physical and mechanical parameters can be interpretated, like shear wave velocity, etc. Even though various studies have been conducted and methods are proposed, uncertainties still exist and the applicability of each method needs be further clarified. A case study on the interpretation of CPT results is performed which based on the measured data from an offshore site close to East Sea, China. This paper focus on clayey soil layers and presents an assessment of CPT data interpretation methods for the derivation of clayey soil’s shear wave velocity. It shows that Long’s method proposed in 2010 (C1) and Cai’s method proposed in 2014 (C2) provide better predictions of shear wave velocity. Additionally, values of soil unit weight used in the shear wave velocity derivation can also be interpretated from CPT data since it shows ignorable effect on the interpretated velocity profile.
Abstract Based on Cone penetration tests (CPT) data, a number of soil’s physical and mechanical parameters can be interpretated, like shear wave velocity, etc. Even though various [...]
L. Hauser*, D. Durán, L. Monforte, M. Arroyo, A. Gens
ISC2024.
Abstract
Variable penetration rates during CPTu may impact cone readings through partial consolidation during penetration but also through viscous soil skeleton behaviour. The latter phenomenon is characteristic of dynamic penetrometers during fast penetration in fine-grained materials where tip resistance increases when the penetration rate increases. In this work, the effect of viscosity on piezocone penetration is investigated based on the numerical simulation of CPTu and triaxial tests using the application G-PFEM and a viscoplastic version of the Clay and Sand Model (CASM). The study highlights that the CPTu results are sensitive to the material parameters controlling viscosity, thus requiring careful calibration in order to obtain realistic CPTu simulations.
Abstract Variable penetration rates during CPTu may impact cone readings through partial consolidation during penetration but also through viscous soil skeleton behaviour. The latter [...]
This paper discusses the numerical and probabilistic modelling of the tunnel construction concerning some not yet completed sections of the Vienna U2 metro line. It presents the algorithm and results analysis of numerical simulation for the step-by-step tunnel construction using the New Austrian Tunnel Method (NATM) in a dense urban environment. The nature and magnitude of subsidence of the earth surface depending on a number of factors involved in the calculation scheme are determined, and all parameters of the stress-strain state of the system "tunnel - ground mass" are obtained. A methodology is proposed for determining reliability by the criterion of additional vertical subsidence of the ground surface which accompanies underground construction. By comparing the results of numerical modelling, empirical calculation and geotechnical monitoring of the metro construction site, it is shown that they correlate well enough with each other. The results of this study can be used to predict the level of the ground settlement during tunnelling works in areas of dense urban development.
Abstract This paper discusses the numerical and probabilistic modelling of the tunnel construction concerning some not yet completed sections of the Vienna U2 metro line. It presents [...]
In this study, artificial neural network, a popular machine learning technique, was used to estimate the consolidation properties of points where no soil investigations have been conducted. The Holocene clay layer at the construction site of Kobe Airport, a large-scale man-made island in Osaka Bay, was targeted to estimate the consolidation properties. The performance of an estimation model built with artificial neural network depends on the datasets used during the training phase. Therefore, the average of multiple estimation results can be used. Numerical simulations using the estimated consolidation properties can accurately reproduce the settlement behavior owing to reclamation during the construction of Kobe Airport. Artificial neural network can easily and objectively estimate the consolidation characteristics of any point based on the existing soil investigation results.
Abstract In this study, artificial neural network, a popular machine learning technique, was used to estimate the consolidation properties of points where no soil investigations have [...]
Site characterisation necessarily relies on engineering judgement, usually combined with some level of statistics to define characteristic values for design purposes. A suitable method for this task is quantile regression, which allows for the definition of lower, upper, and best-estimate characteristic values. The application of quantile regression to homogeneous profiles is relatively straightforward. Although such sites are common in some areas, there is need for a more comprehensive approach to quantile regression that covers the more general scenario of heterogeneous stratified profiles. This paper takes piezocone penetrometer data from a relatively complex seabed site and demonstrates the streamlined application of quantile regression, highlighting and analysing some of the assumptions and choices behind the approach. The work shows the nuances of the method and suggests workarounds for potential scenarios where its application may be challenging.
Abstract Site characterisation necessarily relies on engineering judgement, usually combined with some level of statistics to define characteristic values for design purposes. A suitable [...]