Geotechnical Engineering

A database of 641 fall cone tests on 101 soil samples from twelve countries has been analysed to determine the best mathematical relationship linking undrained shear strength with liquidity index. From the database, it is shown that the use of a linear relationship linking liquidity index and the logarithm of undrained shear strength that uses the commonly assumed 100-fold factor increase in strength from liquid to plastic limit
over-predicts the measured data of soil strength. The use of a factor of about 35 for the ratio between the strength at liquid limit and that extrapolated to plastic limit is shown to be more realistic. Logarithmic liquidity index is examined and found to also correlate strongly with the logarithm of undrained shear strength, however it is shown that no great statistical improvement is present compared with the semilogarithmic
formulation. When considering data of individual soils a power law fitting is shown statistically to be the preferred mathematical function.

A new approach is developed to determine the shear wave velocity in saturated soft to firm clays using measurements of the liquid limit, plastic limit, and natural water content with depth. The shear wave velocity is assessed using the site-specific variation of the natural water content with the effective mean stress. Subsequently, an iterative process is envisaged to obtain the clay stiffness and strength parameters. The at-rest earth pressure coefficient, as well as bearing capacity factor and rigidity index related to the cone penetration test, is also acquired from the analyses. Comparisons are presented between the measured clay parameters and the results of corresponding analyses in five different case studies. It is demonstrated that the presented approach can provide acceptable estimates of saturated clay stiffness and strength parameters. One of the main privileges of the presented methodology is the site-specific procedure developed based on the relationships between clay strength and stiffness parameters, rather than direct correlations. Despite of iterative processes, the presented approach can be easily implemented using a simple spreadsheet, benefiting both geotechnical researchers and practitioners.

Seismic behavior of a structure is highly influenced by the response of foundation and ground. Hence, the modern seismic design codes recommend that the response analysis should be conducted by taking into consideration the whole structural system including the soil-structural interaction. 3D FEM analysis is appealing for soil-structure interaction problems as it can model soil continua and it takes into account the damping and inertial effect of soil. However, for a structure with a large number of piles, it is computationally difficult to carry out full 3D FEM analysis using solid elements for both structure and piles. This paper, investigates the use of 3-node fiber based beam elements for modeling of pile using full-scale lateral loading test on single pile and 3D FEM analysis of single pile and full-scaled bridge pier system. The finite element analysis carried out on the single pile and full-scale bridge pier exhibited that 3-node beam element can adequately simulate the behav...

Natural cementation affects the properties of soils, the interpretation of in situ and laboratory test results, and the selection of criteria for geotechnical design. In this paper, published experimental studies are reviewed, a microscale analysis is presented of the effect of cementation on small-strain stiffness for distinct stress-cementation histories, and the effect of cementation on small-strain velocity and damping is experimentally studied. Observations include the prevailing effects of cementation over effective stress, the coexistence of frictional and viscous losses, and the effects of decementation when the medium is unloaded from the level of confinement prevailing during cementation.Key words: wave velocity, seismic response, stiffness, damping, sampling effects, loading history.

Permafrost degradation in regions of high seismic activity increases the potential for soil liquefaction, which can be a serious threat to transportation and utility infrastructure, as many professionals observed during the November 2002 Denali Earthquake (magnitude Mw 7.9). This project conducted laboratory studies to investigate the liquefaction resistance of frozen and seasonally frozen ground. Researchers examined how soil liquefaction is influenced by freeze-thaw cycles throughout the year, and how liquefaction is influenced by temperature distribution in degrading permafrost. The results of this study will help establish criteria for liquefaction susceptibility in melting permafrost and soils that regularly undergo freeze-thaw cycles.

Compacted sandy soils with addition of bentonite have been used in a variety of geotechnical structures as engineered barriers, such as in landfill liners and hydraulic containment structures. In this study, Igbokoda sand was mixed with bentonite at varying percentages of 0%, 2%, 4%, 6%, 8% and 10% by weight of sand. Strength tests, which include compaction test, California Bearing Ratio (CBR) test and direct shear test, were performed on various sand-bentonite mixtures using standard methods. Hydraulic conductivity tests were also performed on various sand-bentonite mixtures in order to determine their suitability as landfill liner. Results from the tests showed that 8% of bentonite with sand mixture had a hydraulic conductivity below 1×10-7 cm/s, a cohesion value of 250 kN/m3 and a reasonable strength (CBR) value of 54.07% using the West Africa standard compactive method, hence being the safest of the selected varying percentages for the design of a landfill liner.

En este trabajo se presentan los resultados de una serie de equivalencias directas entre el ensayo de penetración dinámica súper pesada (DPSH) y el ensayo de penetración estándar (SPT), a partir de 129 datos recolectados en distintos proyectos de exploración geotécnica ejecutados en Colombia. Las equivalencias entre los resultados de las pruebas se obtuvieron en términos de golpeo, comparando estos para distintas agrupaciones texturales de suelos con base en ensayos de laboratorio, principalmente, de clasificación. Como resultado de un análisis estadístico de estos datos se derivaron cinco equivalencias directas en función a la clasificación granulométrica del suelo, las cuales han sido comparadas con las propuestas de otros autores. Este proceso permitió ampliar el rango de uso para demás texturas de suelo que, actualmente, no habían sido correlacionadas. Palabras clave: caracterización geotécnica, correlación, ensayo de penetración dinámica super pesada (DPSH), ensayo de penetración estándar (SPT).


This paper presents the results of a series of direct equivalencies between the dynamic probing super heavy (DPSH) and the standard penetration test (SPT) based on 129 data collected from different geotechnical exploration projects carried out in Colombia. The equivalences between the results of the tests were obtained in terms of blows, comparing these for different textural groupings of soils based on, mainly, in classification laboratory tests. As a result of a statistical analysis of these data, five direct equivalences were derived formed on the granulometric classification of the soil, which have been compared with the proposals of other authors. This process allows expanding the range of use for other soil textures that had not currently been used correlated.

Soil pollution and groundwater contamination are rampant in urban and rural areas of various developing countries including Nigeria. The quality of groundwater is a vivacious concern for human beings since it is directly associated with the human welfare and it is needed to conserve water resources. This paper x-rays strategic approach for controlling soil and groundwater contamination to enhance the efficiency of civil and environmental engineering design through recent trends and practice which will play a vital role in handling environmental pollution. Strategic approach highlighted involves the formulation and implementation of the major goals and initiatives based on consideration of resources and an assessment of the internal and external environments in which the organization competes. One or more of these approaches are often combined for more cost-effective treatment. The field studies for assessment of contamination comprised of detailed hydro-geological investigations whi...

This research work mainly focuses on stabilization of Ikpayongo laterite using cement blended with Rise Husk Ash (RHA) and Carbide Waste (CW) to promote its physical characteristics. The blending of cement with Rice Husk Ash (RHA) and carbide waste (CW) was done in proportion to determine the required proportion suitable for the stabilization of Ikpayongo laterite. Atterberg limit test, Compaction test, California Bearing Ratio (CBR) test, Specific Gravity, Unconfined Compressive Strength (UCS) test and Durability test were conducted on the laterite sample. The blend of cement with RHA and CW at interval of 0% to 10% displayed better results than the cement treated soil at some percentages. The result showed that at 2% and 10% cement content the MDD of the natural soil reduced from 2.015Mg/m3 to 1.917Mg/m3 and increased to 1.987Mg/m3 respectively, it also reduced to 1.870Mg/m3 when treated with 2% blend of 80% cement 10% RHA 10% CW and increased at 10% of the cement blend. The CBR v...

This paper presents the framework for the interim design guideline for the use of expanded polystyrene (EPS) block geofoam for slope stabilization and repair, based on the findings of the NCHRP Project 24-11(02) Phase I study. The overall objective of this research is to develop a design guideline as well as an appropriate material and construction standard for the use of EPS block geofoam for the function of lightweight fill in slope stability applications. The recommended design methodology included in the framework is based on an assessment of the existing technology and literature. The Phase II work will refine the interim design guideline framework and address some uncertainties in the current state of the practice of analyzing various failure mechanisms included in the design procedure. The completed research will consist of the following five primary research products: (a) a summary of the relevant engineering properties, (b) a comprehensive design guideline, (c) a material a...

This study has been undertaken to investigate the speed control ACIM using field oriented control. The principle of vector control of electric drives is based on the control of both the magnitude and the phase of each phase current and voltage. for this purpose, the study of available conventional and non-conventional approaches has been presented. This paper also presents a clear study which illustrates introduction of efficient vector control of ACIM.

Chalk breaks easily when subjected to human action such as mechanical handling, earthworks operations or pile instal- lation. These actions break the cemented structure of chalk, which turns into a degraded material known as putty, with lower strength and stiffness than the intact chalk. The addition of Portland cement can improve the behaviour of chalk putties. Yet, there are no studies determining the tensile strength of chalk putty–cement blends, the initial stiffness evolution during the curing time and other design parameters such as friction angle and cohesion of this material. This paper addresses this knowledge gap and provides an interpretation of new experimental results based on the dimensionless index expressed as the ratio between porosity and volumetric content of cement (g/Civ) or its exponential modification (g/ Civa). This index aids the selection of the amount of cement and density for key design parameters of compacted chalk putty–cement blends required in geotechnical engineering projects such as road foundations and pavements, embankments, and also bored concrete pile foundations.

Interaction between pile and soil is one the most important cases in Geotechnical engineering and also related sciences. Many of scholars have already explored this issue and examined various aspects of the behavior of piles under influence of different loads. Due to increasing of Micro piles in the last decade and Liquefaction dangerous due to earthquake, in this study micro pile bearing capacity is considered. Numerically, Micro piles behavior for reinforcing of saturated soil is studied. 3-D dynamic finite element method for analyzing of saturated porous condition based on the Biot equations has been used. Governing equations consist of soil displacement and water relative displacement as initial variable are supposed. Cyclic Elasto-plastic behavior of soil under earthquake loading is simulated by using a generalized plasticity theory composing of a yield surface together with non-associated flow rule. In this study, effects of model with one micro pile, without micro pile and model with micro piles group are investigated on the liquefaction potential.

The limitation of soil data due to poor soil investigation process is a common problem in civil engineering project. The finite element method was used to analyse the compatibility of foundation to support silos in Liverpool Docks. Both shallow foundation and pile foundation were considered. The results of the analyses are presented by comparing analytical and numerical solution. Parametric study was considered for each case. There are different results for two types of shallow foundation that had been considered. Strip foundation seemed more reliable than pad foundation, while Pile foundation considered to be first choice due to the satisfactory condition for all factors. ABSTRAK Keterbatasan data tanah karena tidak dilakukannya investigasi tanah secara menyeluruh sebelum proses desain dan konstruksi adalah problem yang umum yang terjadi pada proyek-proyek teknik sipil. Metode elemen hingga adalah dipakai untuk menganalisa jenis pondasi yang dapat mendukung dari silos di Pelabuhan liverpol. Pondasi dangkal maupun pondasi tiang keduanya dipertimbangkan untuk digunakan. Analisa tersebut membandingkan metode numerik maupun analitik. Hasil dari analysa tersebut memperlihatkan hasil yang berbeda dari dua tipe pondasi dangkal. Pondasi strip memberikan nilai yang lebih optimal daripada fondasi pad. Sementara pondasi tiang menjadi pilihan pertama karena kelayakan dari semua faktor yang ditinjau. Kata Kunci : elemen hingga, silo, pondasi tiang dan dangkal

This paper examines biocementation via the microbial-induced carbonate precipitation (MICP) process as an appropriate and promising new technology for stabilisation of loose sand and silty sand deposits as a method to mitigate wind erosion. The technique involves spray treating the sand surface layer with a mixture of cementation and bacterial-cell solutions, the ensuing reactions causing calcite precipitation to occur between the sand grains, thereby lightly cementing them together over time. The bench-scale experimental programme presented investigates the proposed technique's effectiveness for stabilisation of silica and carbonate sands with different gradations, determination of the optimal reagent concentrations, the time-dependent shear strength development for the crustal sand layer following single-and double-MICP spray treatments, as well as wind tunnel experiments. Of particular novelty were investigations of the effect of dew formation on crustal shear strength development with curing period and the efficiency of the MICP treatment for the outdoor environment compared to laboratory-controlled test conditions. The wind tunnel experiments demonstrated that 28-day cured singly MICP-spray-treated crustal sand layers were stable to simulated 20 m·s−1 winds measured at 20 cm above the layer surface.

O presente artigo apresenta resultados de caracterização geotécnica vinculada ao potencial uso do lodo de uma estação de tratamento de chorume (LETC) como material para a cobertura final de um aterro sanitário. Entre as principais propriedades avaliadas está à curva de retenção, a contração e a condutividade hidráulica saturada. Também foram avaliadas as propriedades físicas, químicas e a mineralogia do resíduo. O resíduo mostra em sua composição a presença de minerais de calcita e portlandita. A curva de retenção se caracteriza por apresentar um valor de entrada de ar da ordem de 10kPa, e a condutividade hidráulica saturada da ordem de 1.5x10-5cm/s. Todos os ensaios de secagem efetuados para avaliar a contração e a curva de retenção<br> não mostraram a presença de trincas. Os resultados sugerem que o resíduo tem potencial de uso para um sistema de cobertura final, primeiro por não apresentar risco de formação de trincas e, segundo, pela possibilidade de uso como camada de mat...

ABSTRACT Slope stability analysis of soil with a weak layer sandwiched between two strong layers is considered as a complex geotechnical problem. In this problem, the objective function is non-convex and discontinuous with the presence of multiple strong local minima. Classical optimization techniques fail to converge to a valid solution unless a proper initial trial is adopted. Even though many new optimization algorithms have emerged, they have not been applied to geotechnical problems yet. In the present study, some recent swarm intelligence algorithms are adopted for some complicated example of slope stability problems and benchmarked with the traditional particle swarm optimization algorithm. From the results, it seems the levy flight krill herd algorithm is the most efficient method over proposed algorithms for this kind of problem. Copyright © 2014 John Wiley & Sons, Ltd.

Batang–Semarang Toll Road is a toll road that stretches along 75 km connecting the Regency of Batang with the City of Semarang, within Central Java province. Beringin River morphologically consists of river curves that form an S letter and is situated on the Batang–Semarang toll road along 1279 m. Relocation of river basins is needed to maintain the river hydraulic functionality as natural drainage channel. The river relocation that requires enough wet cross-sectional area resulted in the toll road embankment bordering directly adjacent to the river channel relocation plan. Reinforcement of toll road embankment due to river relocation is performed by using Sheet pile as retaining wall to reduce lateral deformation and increase the safety factor of embankment stability.

— Surface or shallow compaction is one of the earliest, cheapest and commonly used techniques to improve the physical and mechanical properties of loose soil specially for imported structural fill. It is simply rearranging of soil particles to reduce air ratios using surface static or vibrating mechanical effort. Usually, shallow compaction procedure includes subjecting the loose soil to certain number of compacting equipment passes to archive the accepted compaction level; this number of passes is a function of many parameters such as type of soil, initial soil parameters, compacting equipment characteristics and thickness of soil lift. International codes, specifications and handbooks include just guidelines about the required number of passes; accordingly, it is usually determined based on personal experience and field trials. This research has two goals, the first is to estimate the properties improvement of certain natural surface loose soil under certain surface compaction procedure by calculating the enhancement in soil properties after each pass and updating the soil properties for next pass calculations. The second goal is to use the previous approach to develop set of equations to design surface compaction procedure for imported structural fill, this includes calculating minimum compaction equipment characteristics, maximum lift thickness and minimum number of passes to enhance certain imported fill from certain initial condition to certain final condition. The proposed approach for the first goal was verified using case studies and showed good matches, and the developed designing equations for surface compaction procedure were verified using case studies and showed good matches.

Digital geoinformation for the surface and subsurface is virtually never integrated in civil engineering projects. Reasons are that the surface information is gathered by different person’s and that the subsurface information is in different formats from the surface information. Likelihood and uncertainty of subsurface models is not quantifiable. To quantify the likelihood and correctness of the subsurface information the civil engineer would have to have full access to the original data, which is not available due to the none integration of the data. In the last 10 years considerable progress has been made in use of geographic information systems but the progress in the integration of data and the addressing of likelihood of subsurface data is limited.

Blasting is a process of breaking the rock mass to excavate the ore and materials. Many open blasting operations are faced with the apparently conflicting requirements of providing large quantities of fragmented rock and of minimizing the amount of damage inflicted upon the surrounding slopes. A slope in strong hard rock is not necessarily stable, nor is a slope in weathered weak rock necessarily unstable. In some cases the reverse is true, depending on the geometry of joints and weak planes. Many slope failures in hard rock occur with no or very little warning. Detection and monitoring may not be feasible, or require sophisticated instruments and procedures that are not practical at some locations. An important element in avoiding catastrophes is to study the site geology for dangerous conditions, implement the types of blasting procedures that minimize failures, and evaluate the potential use of reinforcement or other mechanical stabilizing procedures. Apart from undesired profile of excavation, the conventional blasting damages the surrounding rock mass and structures like buildings, etc. These damages can be minimized by use of controlled blasting technique. The controlled blasting technique (CBT) is used to produce the desired stability of pit walls / slope. The CBT used for slopes is specifically termed as wall controlled blasting technique (WCBT). WCBT includes buffer blasting, trim blasting, line blasting and pre-splitting. Among these, the pre-splitting is the most commonly used technique. This technique has several advantages such as minimum damage from back-break, enhanced carrying capacity, higher structural stability and stable final pit walls or slope at the designed angle thus improving overall safety of wall / slope.

A small, simple, and economical instructional centrifuge has been developed at the University of Colorado at Boulder to assist in undergraduate geotechnical engineering education. Centrifuge experiments on stability of slopes and retaining walls have been developed. These experiments are conceptually simple, yet fundamental, and do not require elaborate instrumentation and data acquisition. Classical failure patterns discussed in the class can be reproduced in the models. Experimental results can be used to verify such theories as undrained slope stability analysis and Rankine's or Coulomb's lateral earth pressure theories. Each of the tests can easily be conducted up to four to five times in a 2-h laboratory session. Comprehensive laboratory reports can be generated by students discussing both qualitative and quantitative aspects of the tests in relation to the theoretical concepts taught in the classroom. In addition to the experiments on slope stability and lateral earth pressures, demonstration experiments on footings and reinforced earth slopes have also been conducted using the instructional centrifuge.

Quito, Ecuador, is a city at risk of many hazards including earthquakes, volcanic eruptions and landslides, compounded by the widespread presence of problematic volcanic soils known as Cangahua. This paper presents the preliminary results of data analyses undertaken on a new geotechnical database for Quito, compiled from a variety of sources. It is envisaged that this database will be utilised primarily for improving our understanding of landslide hazard drivers in communities in and around the city. The preliminary statistical analyses include probability density functions and regression models for soil parameters. A difference in geotechnical variability between the north and the south of the city was observed. The study also presents data from unmanned aerial vehicle (UAV) mapping of an informally constructed hillside community in Quito, identifying house-scale slope features (e.g. cut slopes and house loading) that may affect local landslide hazard processes. Together, the statistical analyses of these datasets will provide the inputs for physics-based stochastic slope stability modelling. Recommendations for future data collection are given to support the development of a higher resolution Quito database and facilitate the improvement of community-scale slope stability assessments.

Moisture content is one of the most crucial factors influencing soil strength. This paper deals with the effect of moisture content and density on the shear strength parameters of WOZEKA-GIDOLE road elastic silt (expansive) embankment soil under dry, wet (partially saturated), OMC and saturated conditions in relation to slope stability analysis. The wide distribution of expansive soil in Ethiopia creates problems in many field of construction such as excavation, slope stability and foundation in understanding their engineering characteristics especially the behavioral changes in dry and saturation condition. In this study, samples were collected from a slope construction road site in WOZEKA-GIDOLE, southern Ethiopia. At a constant grading of a soil its effect on strength, swelling pressure and index properties value has been undertaken, as soils are to be used for making road pavement, embankments. The stability of an embankment will greatly be influence by the shear parameters which are depend upon the degree of compaction. So soil specimen were compacted in the laboratory and the optimum moisture content and dry densities were identified. After compaction soil was tested at the dry side of optimum water content at w = 5%, partially saturate of the optimum at 10%, at 15% OMC and at 20% saturation condition at 1.3 gm/cm 3 , 1.4 gm/cm 3 and 1.55 gm/cm 3 (MDD) dry densities. Parameters of shear strength (C) and (ϕ) were obtained from triaxial shear test (UU) and shows the compacted elastic silt soil behaves like a granular soil on the dry side of optimum water content (5% and 10%) and a reduction in angle of friction and an increase in cohesion are observed as the compaction water contents approach the optimum value. Cohesion shows a slight increase as moisture content increases whereas friction angle highly decreases with increasing moisture content at constant density. The shear strength parameters were used for stability analysis with software GEOSLOPE/W 2018 with Limit equilibrium based methods to calculate the factor of safety (FOS) and locate critical failure arc. The slope stability analysis of elastic silt soil has been done and is used in under different conditions to evaluate slope stability. Analysis of embankment at different heights of the slope with Morgenstern-Price's analysis method. In the present study varying the density and moisture has been affect the properties of expansive soil namely elastic silt soil. Finally constant grading of soil is a technique for modification the geotechnical properties and improving slope stability of embankment and increasing the dry density and decreasing height of embankment, the undrained shear parameters (C & Φ) are improved.

 Abstract-Aeronautical Data Chain is a conceptual representation of the path that a set or element of aeronautical data takes from its origination up to end-use. There are classical databases such as navigation or terrain database and configuration files for modularity and portability purposes. These databases can be used to activate or deactivate software items, adapt the software computation to the aircraft configuration, or provide computation data. The RTCA DO-200B establishes three Data Process Assurance Level (DPAL) as the level of rigor, representing the amount of verification and validation tasks performed, during data processing to assure data quality. This paper presents four different and complementary validation techniques to ensure correctness for Aeronautical Databases. This work aims to cover the existing gap in the available standards, presenting and exemplifying some proposed techniques. It also presents some techniques and provides different comparisons and specific intentions. At the end, some relevant needs of qualified tools are discussed to ensure that the use of techniques can be automated, and credits can be sought using tools.

This report presents the results of a modified static puncture resistance test which also known as CBR puncture resistance test which was held on 18/05/2017. The tests were carried out by researcher/consultant from the Faculty of Civil Engineering, Universiti Teknologi MARA Shah Alam, Selangor. The tests were conducted using a 500 kN Universal Testing Machine together with a 150 mm diameter CBR Mould and a 50 mm diameter of flat-ended Cylindrical Plunger.

— In digital communication system, digital information can be sent on a carrier through changes in its fundamental characteristics such as phase, frequency and amplitude. The use of a filter plays an important part in a communication channel because it is effective at eliminating spectral leakage, reducing channel width, and eliminating interference from adjacent symbols (Inter Symbol Interference) ISI. It describe the developed and dynamic method of designing finite impulse response filter with automatic rapid and less error by an efficient genetic and neural approach. GA and Neural are powerful global optimization algorithm introduced in combinational optimization problems. Here, FIR filter is designed using Genetic, Neural approach by efficient coding schemes. We need to design these filters with some constraints imposed by requirements of the communication system in which we are going to use them. The use of optimization techniques have been proved to be quite useful towards the design of those digital filters with certain specifications. This paper reviews about the uses of optimization systems in digital filter design.

 Abstract— Data Leakage can be referred as the unauthorized transfer of classified information from a computer or data centre to the outside world. Big data is an evolving term that describes any voluminous amount of structured, semi-structured and unstructured data that has the potential to be mined for information. The data loss in such huge massive data sets may cause critical vulnerabilities. In this paper we proposed a novel model in Hadoop master/slave architecture for data leakage prevention with LRA algorithm. The LRA algorithm evaluates the Least Reliable Agent and sends it to the DLA (Data Leakage Avoider). DLA prevents the NameNode from allocating data to these agents.

Correlations are presented to compute the mutual solubilities of CO2 and chloride brines at temperatures 12–300°C, pressures 1–600 bar (0.1–60 MPa), and salinities 0–6 m NaCl. The formulation is computationally efficient and primarily intended for numerical simulations of CO2-water flow in carbon sequestration and geothermal studies. The phase-partitioning model relies on experimental data from literature for phase partitioning between CO2 and NaCl brines, and extends the previously published correlations to higher temperatures. The model relies on activity coefficients for the H2O-rich (aqueous) phase and fugacity coefficients for the CO2-rich phase. Activity coefficients are treated using a Margules expression for CO2 in pure water, and a Pitzer expression for salting-out effects. Fugacity coefficients are computed using a modified Redlich–Kwong equation of state and mixing rules that incorporate asymmetric binary interaction parameters. Parameters for the calculation of activity and fugacity coefficients were fitted to published solubility data over the P–T range of interest. In doing so, mutual solubilities and gas-phase volumetric data are typically reproduced within the scatter of the available data. An example of multiphase flow simulation implementing the mutual solubility model is presented for the case of a hypothetical, enhanced geothermal system where CO2 is used as the heat extraction fluid. In this simulation, dry supercritical CO2 at 20°C is injected into a 200°C hot-water reservoir. Results show that the injected CO2 displaces the formation water relatively quickly, but that the produced CO2 contains significant water for long periods of time. The amount of water in the CO2 could have implications for reactivity with reservoir rocks and engineered materials.