Geotechnical Engineering Works Research Articles

Integrating life-cycle environmental impact and costs into geotechnical design

Construction and infrastructure projects account for a large share of global greenhouse gas emissions. Included in these projects are geotechnical engineering works, which cause environmental impact and costs throughout their life cycle. In the geotechnical design process, the geotechnical engineer often has design choices where different methods and materials can be used. If assessments of environmental impact and costs were to be integrated into the geotechnical design process, the geotechnical work could be made more sustainable. As a result of this, there is a need for research on integrating the assessments of environmental impact and costs into the geotechnical design process. This paper, therefore, presents a methodology showing how life-cycle assessment and life-cycle cost analysis could be integrated into the geotechnical design process. The presented methodology is then illustrated in a practical example for assessing the climate impact and costs of high-speed railway embankment fill methods.

Approximating Helical Pile Pullout Resistance Using Metaheuristic-Enabled Fuzzy Hybrids

Piles have paramount importance for various structural systems in a wide scope of civil and geotechnical engineering works. Accurately predicting the pullout resistance of piles is critical for the long-term structural resilience of civil infrastructures. In this research, three sophisticated models are employed for precisely predicting the pullout resistance (Pul) of helical piles. Metaheuristic schemes of gray wolf optimization (GWO), differential evolution (DE), and ant colony optimization (ACO) were deployed for tuning an adaptive neuro-fuzzy inference system (ANFIS) in mapping the Pul behavior from three independent factors, namely the embedment ratio, the density class, and the ratio of the shaft base diameter to the shaft diameter. Based on the results, i.e., the Pearson’s correlation coefficient (R = 0.99986 vs. 0.99962 and 0.99981) and root mean square error (RMSE = 7.2802 vs. 12.1223 and 8.5777), the GWO-ANFIS surpassed the DE- and ACO-based ensembles in the training phase. However, smaller errors were obtained for the DE-ANFIS and ACO-ANFIS in predicting the Pul pattern. Overall, the results show that all three models are capable of predicting the Pul for helical piles in both loose and dense soils with superior accuracy. Hence, the combination of ANFIS and the mentioned metaheuristic algorithms is recommended for real-world purposes.

Modelling underground excavations in rock masses with anisotropic time-dependent behaviour

When modelling rock masses that behave anisotropically and in addition present a time dependent behaviour, it is relevant to select a constitutive model able to represent their actual behaviour realistically. This article presents an alternative anisotropic time-dependent constitutive model able to predict the coupling between anisotropic behaviour and time-dependent (or viscous) behaviour. The viscous behaviour is simulated with the Burgers model and all elastic springs and viscous dashpots are considered to exhibit transversely isotropic properties. The proposed constitutive model has been implemented in the finite element method software CODE_BRIGHT. To verify the basic anisotropic elastic solution, it has been compared with that of PLAXIS results. And to verify the isotropic viscoelastic solution, it has been compared with analytical solutions. Furthermore, the proposed constitutive model has been used to predict the behaviour of samples from laboratory tests. Finally, parametric analyses have been carried out to investigate the influence of different factors on tunnelling responses, including the selection of different constitutive models, anisotropy of initial stresses and anisotropy of material properties. The proposed model provides an alternative method for the preliminary design of geotechnical engineering works involving geomaterials that exhibit anisotropic time-dependent behaviour.Article highlights• An anisotropic time-dependent model has been implemented in CODE_BRIGHT and validated.• The model can predict the coupled anisotropic time-dependent behaviour of geomaterials.• Parametric analyses have been performed to study the influence of different factors in ground response.

Monitoring Flexure Behavior of Compacted Clay Beam Using High-Resolution Distributed Fiber Optic Strain Sensors

Abstract Understanding the mechanical characteristics of clayey soil is critical to estimate the stability of clay-related geotechnical engineering works. However, the distributed information of the internal deformation of clay is hard to capture through traditional methods. In this paper, a set of four-point bending tests were performed on a compacted clay beam instrumented with fiber optic strain sensors to investigate the flexure and cracking behaviors. The optical frequency domain reflectometry technique with high spatial resolution and precision was employed to establish a distributed strain sensing (DSS) system in this study. The results show that the DSS system exhibits a high accuracy in the collection of the clay deformation in terms of compression, tension, and cracking. The comparison of the internal strain profiles with the observation of particle image velocimetry analysis system verifies the feasibility of fiber optic sensing technology in the quantitative assessment of clay deformation. The performance of fiber optic sensors in the rebound deformation and creep deformation monitoring was preliminarily issued in the study. In addition, the progressive failure on the fiber–soil interface was analytically studied to evaluate the deformation compatibility between the fiber and surrounding clayed soil. The conclusions drawn in this paper can help to guide the state interpretation of clayey soil instrumented with fiber optic sensors.

Cracking mechanisms of a medium-grained granite under mixed-mode I-II loading illuminated by acoustic emission

Cracks at various scales in rock masses are often subjected to mixed-mode I-II loadings in Earth's dynamic processes and geotechnical engineering works. Insightful understanding of the macroscopic and microscopic cracking mechanisms of rocks under this loading condition is of far-reaching significance. To investigate the effect of the loading condition and granite heterogeneity on the cracking mechanism, we conduct three-point bending tests on pre-notched semi-circular medium-grained granite specimens. For comparison, identical tests are also conducted on polymethyl methacrylate (PMMA) specimens. The results show that the initiation angles of the macrocracks in granite are less influenced by the loading condition as compared with the more homogeneous PMMA. Based on the monitoring of the acoustic emissions (AEs), we find that the microcracks under mixed-mode I-II loading do not nucleate as easily as compared with that in mode I case. For the AE event density contours characterizing the fully-developed fracture process zones, their shape is sub-circular and symmetric with respect to the pre-existing notch under mode I loading, while those under mixed-mode I-II loadings are irregular and asymmetric. Most of the macrocrack paths traverse the high AE event density region. As the mode II stress intensity factor (KII) increases, the AE events with higher energy tend to concentrate beside the crack paths in front of the notch tips. The moment tensor inversion suggests that the presence of mode II loading component alters the AE source mechanisms in terms of the temporal evolution characteristics of event-type ratios preceding the unstable propagation of macrocracks.

Korelasi Point Load Index dan Uniaxial Compressive Strength pada Satuan Batupasir dan Batulempung Formasi Latih untuk Penentuan Koefisien Kekuatan Batuan di Pit X Tambang Batubara PT Berau Coal, Kalimantan Timur

Physical and mechanical properties of rock for engineering purposes are indispensable for any civil/construction, mining and other engineering requirment. The results of the uniaxial compressive strength (UCS) test are very much needed in various geotechnical analyzes or engineering, in particular in the mining industry in relation to the calculation of the pit slope design and other mining infrastructure. Rock samples used in this study were obtained from the results of geotechnical drilling (full core drilling). The rock engineering properties test to obtain UCS and PLI values was carried out in the laboratory. Testing the rock hardness index using the point load index (PLI) can be done more quickly, cheaply, practically and can use rock samples with a variety of sample shapes. The focus and object of the research are mudstone and sandstone units as part of the Lati Formation. These two types of layers are the most dominant rock types as a constituent of the pit slopes in the research area. To ensure that the correlation results are in accordance with the rules of scientific research, the distribution of UCS and PLI data from laboratory test results is verified using a statistical approach / testing. Correlation and analysis between the two rock engineering properties test results are very useful for geotechnical analysis data input. The coefficient or constant values obtained can be used to determine the rock strength values used in various geotechnical analyzes so that the analysis can be carried out more efficiently, effectively and quickly and can support geotechnical engineering work.

Experimental Study on Lateritic Soil Stabilization with Waste Engine Oil and Lime

The world wide concern for cleanup, protection and enhancement of the environment has development of a sub discipline within the field of geotechnical engineering; namely Geoenvironmental, which is concerned with the application of geotechnical engineering to environmental control. It is within this area that the concepts of stabilization, solidification, reuse and recycling wastes in geotechnical engineering works are popularly encountered. The cost of the construction materials has rapidly increased and hence stabilization of soil using admixtures becomes Cost effective and eco-friendly blocks. Thus waste engine oil and natural lime considerably promise to reduce the cost of construction or alternative material that would be suitable for construction activities and also reduces the disposal problem and hence reduces contamination of soil and water.

Probabilistic characterization of subsurface stratigraphic configuration with modified random field approach

Accurate and precise characterization of the subsurface stratigraphic configuration (geological model) at a given site is crucial to geotechnical engineering work. The uncertainty in the derived stratigraphic configuration can be significant, due to the strata's complexity and inherent spatial variability coupled with the limited availability of borehole data. The characterization and reduction of this uncertainty should be part of any site characterization project. This paper presents a method for characterization of the subsurface stratigraphic configuration with limited borehole data. Within the framework of the proposed method, the spatial correlation between the existence of a stratum in one subsurface zone and that in the other subsurface zone (or the spatial correlation of the existence of the stratum) is captured by an autocorrelation function determined with the maximum likelihood principle. The initial stratigraphic configurations are first sampled with the conditional random field theory. Next, the maximum-a-posteriori (MAP) estimates of the initial stratigraphic configurations are derived using Markov Chain Monte Carlo (MCMC) and taken as the final stratigraphic realizations. The effectiveness of the proposed method and its advantages over the existing stratigraphic characterization methods are demonstrated through a series of comparative analyses. The versatility of the new approach in modeling the 3-D stratigraphic configuration is further revealed through a case study of a site in Western Australia. This paper adds to the literature on stratigraphic uncertainty characterization and provides a basis for a risk-based geotechnical assessment that considers geological and geotechnical uncertainties.

Life cycle assessment and life cycle cost analysis for geotechnical engineering: review and research gaps

Geotechnical engineering work contributes to the total environmental impact and monetary cost occurring from the construction sector. Decisions made regarding geotechnical engineering aspects have a profound effect on the environmental impact and the monetary cost of the structure during its life cycle. Life Cycle Assessment (LCA) and Life Cycle Cost Analysis (LCCA) are established methods for assessing the environmental impacts and monetary cost from construction works. This paper presents the results from a literature review of 56 published papers regarding the current situation of the use of LCA and LCCA methods in geotechnical engineering. It is found that only limited research has been published in applying LCA and LCCA to geotechnical engineering structures. Further research should focus on developing a framework using LCA and LCCA for geotechnical engineering structures and also identify and fill data gaps in computer software databases. This would help geotechnical engineers in their daily work to reduce the environmental impact and monetary costs throughout the life cycles of the designed structures.

Research of the Behavior of Clay Materials with Double Porosity

This contribution presents results from a series of compression and undrained triaxial tests to study the mechanical behavior of dump clay from the north of Bohemia. The use of these materials as a foundation for construction can’t be achieved without the adoption of some precautions. This comes from embankment, formed by digging the ground (altered claystone), up to the level of coal mining which is in a sub horizontal stratigraphic layer. A potential static liquefaction behavior was observed in undrained tests for high confinement stress. A structural collapse was noticed with the results obtained in the triaxial test. This collapse is characterized by an unexpected large decrease in deviator and mean effective stress. The soils formed have strength properties that are potentially dangerous. These concepts can improve the use of these kinds of soils in geotechnical engineering work. It continues and expands the results obtained in previous research, especially the future problematic use of these materials as the foundation soil for line or building structures.

Construction of a 3D Stratum Model Based on a Solid Model

A three-dimensional stratum model stratum model is a useful auxiliary tool for geotechnical engineering and other exploration work. The existing methods for stratum model construction lack complete topological descriptions of entities, so it is difficult to apply them to 3D geological modeling with complex geometric structures and complex topological relationships between modules. To solve the above problem, in this paper, the boundary representation method is used to represent the arbitrarily-shaped geological entities, and the half winged-edge-face structure topological structure is proposed to describe the topological information of the stratum model for a complex entity. The topological structure can record the topological information of the solid stratum model completely, thereby providing the basis for operations with the model and the applications of various algorithms. Based on this topological structure, the construction process for a 3D solid stratum model is proposed. The reliability and effectiveness of the constructed 3D solid stratum model are verified by an engineering case. The solid stratum model not only solves the geological modeling problem with respect to complex geometric and topological relations, but also provides a new method and idea for 3D geological modeling.

Effect of water contamination on transmissivity behaviour of nonwoven geotextile

Nonwoven geotextiles are one of the most widely used geosynthetic materials in drainage and filtration in geotechnical engineering works and applications. In the present study, drainage property of geotextile fabric with three levels of water contamination (20, 40, and 60 gpl) and with clean water has been studied with the variation of transverse loads (1, 3, 5, and 7 kPa) and fabric mass density (300, 600, and 900 g/m2). Transmissivity of geotextile is found to be lower at higher level of water contamination. The effect of water contamination concentration is higher for fabric with higher mass density. However, the effect of contamination on geotextile material is lower at higher transverse load. The effect of transverse load on transmissivity of geotextile is higher for 300 g/m2 as compared to 600 and 900 g/m2. Although the reduction in transmissivity of fabric with higher mass density (900 g/m2) is higher, still the fabric exhibits better transmissivity behaviour as compared to 300 and 600 g/m2.

Effect of xanthan gum biopolymer on dispersive properties of soils

PurposeNowadays, application of biopolymers on geotechnical engineering works is booming to avoid the harsh effects on environment by using conventional methods for soil treatment. In this present study, xanthan gum (XG) is used as a biopolymer to improve dispersive properties of the soils because these soils are easily prone to erosion, which may lead to the damage of many hydraulic structures.Design/methodology/approachIn the present study, attempts are made to reduce the dispersive potential and increase the Strength and erosion resistance by treating the soils with various percentages of XG (0.5%, 1%, 1.5% and 2%). To assess the dispersive potential and erosion resistance of soils, tests such as double hydrometer test, pinhole erosion test, crumb test and cylinder dispersion test were conducted. Further tests were expanded for its geotechnical characteristics such as Atterberg’s limits, standard proctor test, unconfined compressive strength test, one-dimensional consolidation for various curing days. Scanning electron microscopy analysis was also carried out to know the microscopic view towards its particle orientation and bindings. Chemical tests such as sodium absorption ratio, total dissolved solids (TDS) and percentage sodium (PS), electronic conductivity and pH tests were also conducted.FindingsThe results revealed that there is a reduction in the dispersive potential of XG treated soils for all the combinations. Addition of XG decreased the PS in the soil as a result dispersivity of soil decreased. Strength and erosion resistance of soil increased with the addition of XG and 1% XG was observed to be the optimum percentage for stabilizing these types of soils.Practical implicationsThese results will be very much helpful for engineers when they come across with dispersive soils for better handling and management.Originality/valueThe originality of this study was an attempt towards sustainable development by treating dispersive soils with XG and effects on various geotechnical and dispersive characterizes.

Effect of basalt fiber inclusion on the mechanical properties and microstructure of cement-solidified kaolinite

The polypropylene fibers, which are currently attracting enormous attention in various geotechnical applications, carry a risk of aging under an integrated effect of heat, oxygen, light and other environmental factors, causing potentially infrastructure failure. An eco-friendly and biologically inactive material – basalt fiber, which has excellent natural resistance to aging and can eliminate aging-associated disasters, deserves more attention in geotechnical field. However, quite few studies are available on the beneficial reuse of basalt fibers to improve the engineering performance of soils. Therefore, this study aims to incorporate the sustainable basalt fiber and clarify how its inclusion impacts the mechanical properties and microstructure of cemented kaolinite. The experimental programs are comprised of three types of tests, i.e. two to examine the compressive strength and triaxial shear behavior and one to evaluate the microstructure properties. The results indicate that the basalt fiber reinforcement plays an essential role in enhancing the compressive strength and peak deviatoric stress of cemented and uncemented kaolinite. The inclusion of basalt fibers improves the ductility and weakens the brittleness of cemented kaolinite. The compressive strength increases with basalt fiber content and curing time, and reaches the peak at the fiber content of 0.2%, followed by a reduction due to the formation of weak zone at higher fiber content. The peak deviatoric stress is elevated until reaching the maximum at the basalt fiber content of 0.4%, after which further addition of basalt fiber tends to reduce its reinforcing effect. The peak deviatoric stress increases as the basalt fiber length is shortened and the confining pressure is raised. The strength gain of cement-basalt fiber inclusion is much more than the sum of strength increase induced by them individually. The combination of basalt fiber and cement has the virtues of both cement-stabilized and basalt fiber-reinforced kaolinite. The SEM analysis reveals that the mechanical interaction in the form of interface bonding and friction between kaolinite particle, cement hydration product and basalt fiber is the dominant mechanism controlling the reinforcement-cementation benefits. The bridging effect (reinforcement) of basalt fibers and binding effect (cementation) of hydration products make a major contribution to the formation of stable and interconnected microstructure, which results in an evident improvement in the mechanical behaviour of cemented kaolinite. The combination of basalt fiber and cement stabilization would be an innovative and effective method for geotechnical engineering works such as soft ground improvement.

Experimental Study on Influence Factors and Empirical Formula of K0 for Coarse Grained Soil

The earth pressure coefficient at rest K0 is a key mechanical parameter of soil, so studying K0 of coarse grained soil has important theoretical value and practical significance in geotechnical engineering works. To investigate the influence factors of K0 for coarse grained soil, a series of K0 compression tests for a sandy gravel and a rockfill were conducted by utilizing a newly-developed large-scale K0 device. The test data show that there is a negative linear correlation between K0 and initial relative density Dr0. The data also show that the increasing vertical effective stress σ′v, will decrease the K0 value, and the effect of low σ′v, on the K0 is more obvious. Large-scale consolidated drained (CD) triaxial tests for soils used for K0 compression test were carried out, and according to the data of CD triaxial tests and K0 compression tests the correlation between K0 and effective internal friction angle ϕ′ is established. Based on the result, an empirical equation is presented. This equation can be used to predict the K0 value of the coarse grained soil under a random consolidation condition and stress condition according to the value of ϕ′. Furthermore, this empirical formula is verified by K0 compression tested data.

Intelligent Computing Based Formulas to Predict the Settlement of Shallow Foundations on Cohesionless Soils

Introduction:Although it is a regular duty of geotechnical engineers to evaluate how much shallow foundation settles in the granular soil, there is no well-approved formula for this task. The intent of this research is to develop a formula that is adequately simple to be used in routine geotechnical engineering work but complete enough to address the behavior of granular soil associated with the settlement issue.Methods:Cone penetration test and foundation load test data were used to generate a formula that can predict the settlement. Genetic Programming (GP) based Symbolic Regression (GP-SR) and artificial neural networks were used to develop an optimized formula. Settlements were also calculated using the finite method and compared to the results of the developed formula.Results and Conclusion:Two formulas were developed using SR, and several models were developed using ANN. ANN model 1 has the highest R2value (0.93) and the lowest MSE (0.16) among all developed ANN and GP-SR models. FEM settlements were almost double the measured ones in some instances.

Improvement of the Mechanical Characteristics of Soil Contaminated with Lubricant Oil – Cal Mix

The demographic and technological evolutions are confronted by geo-environmental problems. When chemicals or contaminants are introduced into the soil, they affect the soil properties such as the grain size curves, the structure, compressibility and stress-strain behaviour. However, the classical soil mechanics models and methods to incorporate the effects of contaminants have not yet been developed. In this study the proposed analysis of geotechnical structure involving effect of chemicals contaminants such as a wasted lubricate oil with lime on the main factors affecting the behaviour of a compacted soil mass and the analysis of a granite residual soil involving effect of the moisture on the compressibility and shear stress behaviour. These concepts can improve the use of these kinds of soils in geotechnical engineering works.

Comparative Study on Soil Stabilization with Polyethylene Waste Materials and Binders

In some cases, the production of solid waste is experiencing an uncontrolled and continuous increase, especially wastes from plastic products. Given that the process of transforming plastic waste into raw material involves high energy consumption, plastic can be used in geotechnical engineering works. This paper is based on comparing two solutions to improve the soil parameters. The first solution is to improve the soil with plastic waste material and the second solution is to improve the soil with cement. Ongoing tests, performed as a part of the research program have shown the effect of the polyethylene waste material and cement on soil mechanical parameters, cohesion and internal friction angle.

ANALISIS NUMERIK PENGGUNAAN GEOTEKSTIL DI LAPISAN TANAH DASAR PADA PROYEK PEMBANGUNAN JALAN PONCOSARI-GREGES (KABUPATEN BANTUL, PROPINSI D.I. YOGYAKARTA)

Geotextile is normally used in geotechnical and other civil engineering work. Geotextiles have been increasingly applied as reinforcement in road embankments. The purpose of this study is to develop the back calculation on safety factor of the use of geotextile as the reinforcement in road embankment considering the displacement in the Proyek Pembangunan Jalan Poncosari-Greges Kabupaten Bantul, D.I. Yogyakarta. The numerical analysis of the road embankment stability was analyzed by finite element method using PLAXIS. Plane strain model was used in this study to calculate the displacement of the road embankment. Analysis results showed that the safety factor obtained by analysis using PLAXIS on the embankment reinforced geotextile was 1.53, which was greater than the standard of safety factor of 1,2. This study concluded that the road embankment was a safe soil construction for the Project of Jalan Pocosari-Greges Yogyakarta.

Stabilization Of Marine Clay Using Biomass Silica-Rubber Chips Mixture

Marine clay is found widely along the coastal area and had caused expensive solutions in the construction of coastal highways. Hence, soil stabilization was suggested by some consultant to increase the strength of this soil in order to meet the highway construction requirement and also to achieve the specification for the development. Biomass Silica (BS), particularly the SH85 as a non-traditional stabilisation method, has been gaining more interest from the engineers recently. Rubber chips (RC), derived from waste rubber tyres, are considered ‘green’ element and had been used previously in some geotechnical engineering works. This paper presents the effect of using BS and RC as a mixture (BS-RC mixture), to increase the strength of marine clay for highway construction. Samples of marine clay, obtained from the West Coast Expressway project at Teluk Intan, Perak, were oven dried and grind to fine-grained sized. The marine clay was mixed with 9 % by weight proportion of BS- RC; that were 8%-l% and 7%-2%, respectively. For comparison purposes the result of BS-RC was compared to the result of stabilization by using 9% BS only. Laboratory tests were then carried out to determine the Atterberg limits and compaction characteristics of the untreated and treated marine clay. The Unconfined Compressive Strength (UCS) of the untreated and treated marine clays, compacted at the optimum moisture content was later obtained. The treated marine clay was tested at 0, 3 and 7 days curing periods. The results show that the Plasticity Index of BS-RC treated marine clay was lower than the untreated marine clay. From the UCS test results, it is shown that BS-RC mixtures had significantly improved the strength of marine clay. With the same percentage of 9% BS-RC, the increased of BS from 7% to 8% increased the UCS further to about six times more than untreated marine clay soils in 7 days curing period. The strength gained by using BS-RC at 8%-1% is slightly below the strength by using 9% BS only. From the experimental results, it is shown that BS, in the form of SH85, admixed with rubber chips could significantly improve the strength of marine clay soils.