Engineering Geological Units Research Articles

Remote Sensing and GIS in Landslide Management: An Example from the Kravarsko Area, Croatia

The Kravarsko area is located in a hilly region of northern Croatia, where numerous landslides endanger and damage houses, roads, water systems, and power lines. Nevertheless, natural hazard management plans are practically non-existent. Therefore, during the initial research, a landslide inventory was developed for the Kravarsko pilot area based on remote sensing data (high-resolution digital elevation models), and some of the landslides were investigated in detail. However, due to the complexity and vulnerability of the area, additional zoning of landslide-susceptible areas was needed. As a result, a slope gradient map, a map of engineering geological units, and a land-cover map were developed as inputs for the landslide susceptibility map. Additionally, based on the available data and a landslide inventory, a terrain stability map was developed for landslide management. Analysis and map development were performed within a geographical information system environment, and the terrain stability map with key infrastructure data was determined to be the “most user-friendly and practically usable” resource for non-expert users in natural hazard management, for example, the local administration. At the same time, the terrain stability map can easily provide practical information for the local community and population about the expected landslide “risk” depending on the location of infrastructure, estates, or objects of interest or for the purposes of future planning.

Shear modulus reduction and damping ratios curves joined with engineering geological units in Italy

Numerical simulations of seismic site response require the characterization of the nonlinear behaviour of shallow subsoil. When extensive evaluations are of concern, as in the case of seismic microzonation studies, funding problems prevent from the systematic use of laboratory tests to provide detailed evaluations. For this purpose, 485 shear modulus reduction, G\\G0(γ) and damping ratio, D(γ) curves were collected from multiple literature sources available in Italy. Each curve was associated with the related engineering geological units considered in seismic microzonation studies. A statistical analysis of the data was carried out with the aim of shedding light on the significant difference between the laboratory classification of samples and the macroscopic/engineering geological one, provided during seismic microzonation studies. Since the engineering geological classification plays a prominent role in extensive site response evaluations, the outcomes of the present work may be of help at least when preliminary seismic response estimates are of concern. The dataset provides reference information that can serve as key data for large-scale hazard assessments worldwide.

A case study in the research polygon in Glina and Dvor municipality, Croatia–landslide susceptibility assessment of geological units

In this paper, a preliminary analysis of the landslide inventory is presented for the wider area of the municipalities of Glina and Dvor, within Sisak-Moslavina County in Croatia, where LiDAR scanning for 45.85 km2 was conducted. Landslide polygons were outlined based on the visual interpretation of HRDEM derivates. In total, 477 landslides were contoured with an average landslide density of 9.85 per km2. Most of the landslides are characterised as moderate, shallow, and not recent. The spatial relationship between landslides and geological units is expressed with the landslide index. Subsequently, the geological units were grouped into four engineering geological units representing different susceptibilities to landslides. The geological units most prone to landslides are the Eocene, Oligocene, Palaeocene and Jurassic sandstones. Even though all geological units were analysed here, the majority of landslides are within sandstones. A particular emphasis was on landslide occurrence in metamorphic and igneous rocks of the ophiolite sequence, a distinctive characteristic of the research area where less susceptibility to landslide processes was observed. Moreover, to further distinguish the differences between the units in the area a morphometric characteristic (relief) and drainage network was also analysed. The purpose of this analysis was to additionally confirm the landslide susceptibility assessment and the division of geological units into engineering geological units, which again implied the different behaviours between landslides in igneous and metamorphic rocks compared to sandstones. Because the research area is poorly studied regarding landslide susceptibility, relief, and drainage networks, these findings will be a step forward in recognising the relationship between them and creating a base for the development of a landslide susceptibility map for this area.

Regional-Scale Landslide Susceptibility Mapping Using Limited LiDAR-Based Landslide Inventories for Sisak-Moslavina County, Croatia

In this paper, for the first time, a regional-scale 1:100,000 landslide-susceptibility map (LSM) is presented for Sisak-Moslavina County in Croatia. The spatial relationship between landslide occurrence and landslide predictive factors (engineering geological units, relief, roughness, and distance to streams) is assessed using the integration of a statistically based frequency ratio (FR) into the analytical hierarchy process (AHP). Due to the lack of landslide inventory for the county, LiDAR-based inventories are completed for an area of 132 km2. From 1238 landslides, 549 are chosen to calculate the LSM and 689 for its verification. Additionally, landslides digitized from available geological maps and reported via the web portal “Report a landslide” are used for verification. The county is classified into four susceptibility classes, covering 36% with very-high and high and 64% with moderate and low susceptibility zones. The presented approach, using limited LiDAR data and the extrapolation of the correlation results to the entire county, is encouraging for primary regional-level studies, justifying the cost-benefit ratio. Still, the positioning of LiDAR polygons prerequires a basic statistical analysis of predictive factors.

Procedures of engineering geological mapping applied to urban planning in a data-scarce area: Application in southern Brazil

Resultsfrom an engineering geological mapping study of the urban area of Ouro Preto in the state of Minas Gerais, Brazil, are presented. The goal of the study was to verify the efficacy of procedures, methods and classification schemes based on engineering geological mapping principles to generate data and maps for urban planning, restructuring (rehabilitation) and engineering projects. The study was developed at a 1:10,000 scale and based on field and laboratory studies and on the analysis and interpretation of aerial photography and satellite images. The selected study area has been urbanized for over 300 years and requires territorial planning and reorganization of land uses. The area is composed of highly variable rock types, unconsolidated materials and terrain features. Data collection and mapping were performed to identify and delineate 51 engineering geological units in terms of the spatial distribution of geological materials, genetic characteristics, mineralogy, the estimated strength, hydraulic conductivity interfaces and potential failure surfaces. All units were assessed in terms of excavatability conditions, predisposition to erosion and shallow translational landslide, suitability for sustainable urban drainage systems (SUDS), contaminant flow conditions, potential use as construction materials and foundation-related aspects. Recommendations for a detailed site investigation were made, and the suitability of geological materials for engineered fill was evaluated. A constraint zoning analysis was carried out to contextualize urban planning. The adopted procedures, methods and classification schemes were shown to be efficient when implemented in conjunction with intensive field studies and enabled the delineation of units with different engineering geological characteristics that are important for urban planning involving different users.

Engineering geological mapping using airborne LiDAR datasets – an example from the Vinodol Valley, Croatia

ABSTRACT This paper presents the potential of airborne LiDAR digital terrain model (DTM) for engineering geological mapping in geologically complex and forested area. The multipurpose, comprehensive engineering geological map is created for the pilot area (16.75 km2) located in the Vinodol Valley, Croatia. Eight topographic datasets were derived from 1-m DTM and visually interpreted to identify lithologies and geomorphological processes. In total, 12 engineering geological units, more than 500 landslides, and gully erosion phenomena are outlined in the pilot area. Results confirmed the greatest potential of visual interpretation of LiDAR derivatives for mapping of geomorphological processes in a large scale. On the other hand, this method allowed identification and mapping of engineering formations that are basic engineering geological units appropriate for the medium-scale engineering geological maps. The produced map represents a valuable tool for a wide range of planning and engineering purposes, as well as for geological hazard and risk assessment.

Geomorphological, Geological and Engineering Geological Aspects for Sustainable Urban Planning of Mymensingh City, Bangladesh

Geomorphological, geological and engineering geological information is used as the base data to characterize the subsurface condition and for sustainable urban planning and development of the rapidly expanding Mymensingh city. Extensive field work has been completed to get the realistic scenario, data and samples have been collected from surface and subsurface with auguring and geotechnical boring. The laboratory tests have been performed following standard laboratory procedures. Geomorphologically the area is broadly classified into Older Floodplain or Mymensingh Terrace and Younger Floodplain. These two flood plains are separated by Old Brahmaputra River. Geologically the area is mainly covered by the recent alluvial flood plain deposits which are underlain by the Pleistocene Madhupur clay deposits. The Younger Flood Plain deposit consists of mainly unconsolidated fine to medium sands with some silt and clay whereas the Older Flood Plain deposits are mainly consisting of silty clay and fine to medium sand. Moderately compacted sediments of older flood plain deposit are suitable for urban development. Based on geotechnical characteristics and the N values (blow counts of Spontaneous Penetration Test, SPT) of the subsurface sediments, the study area is classified into four Engineering Geological Units. Unit I indicates loose soil and is suitable for shallow foundation. Unit II is indicating compact soil packing; N value of these two units increase with depth and would be good for heavy foundation. Unit III is suitable for shallow structures. Unit IV, which is composed of mostly clay, silty clay and sand with highly compressive organic clay, is recommended to avoid any heavy construction and could be used as open place, water retaining zone etc. Beside the geological and engineering geological study details hydrology and hydrogeological and a systematic study on seismic hazards are strongly recommended before planning of urban area.

Engineering Geology of Sidosari Area, Magelang, Central Java, Indonesia

Development of settlement area in Sidosari area and the surroundings requires complete understanding of the engineering geological conditions, including susceptibility to landslides, to prevent damaged properties and loss of lives. Surface engineering geological mapping at a 1:25000 scale was conducted to develop a detailed landslide susceptibility map for spatial planning and to identify most controlling factor of landslides in the research area based on conditions of geomorphology, rock and soil, geological structure, groundwater seepage, and land use. The engineering geological mapping showed that landslides commonly occurred in the moderate slopes of the denudational hill landform having slope inclination ranging from 9 to 17°, in the areas covered by residual soils of the vitric tuff 2 unit, in the areas of no groundwater seepage, and in the settlement areas, including in Kranjang Lor area where soil creeping occurred. The high susceptibility zone covered 55.5 % of the research area and was characterized by having slope inclinations ranging from 9 to 35°, engineering geological units of vitric tuff 2 and tuff breccia, and land uses of rice and dry fields and settlement. The low cohesion and very high swelling potential of the residual soils of the vitric tuff 2 unit were considered to be the main controlling factor of landslides in the research area.

Geophysics, geochemistry and engineering geology: how disciplines combine to improve mine slope design in the Pilbara detrital valleys of Western Australia

Abstract Cenozoic age detrital sequences in the Pilbara region of Western Australia are becoming a focus for engineering geological and hydrogeological investigations with an increasing number of final open-pit walls developed in these materials for iron ore mining. Historically, detrital sequences were classified chronostratigraphically. However, within each chronostratigraphic unit exist sub-units of variable engineering geological and hydrogeological character. As the majority of drill-hole data from Pilbara iron ore mines is derived from reverse circulation techniques, a methodology to identify the engineering geological units through downhole geophysics and geochemical assays was required to progress model development to the level of detail required for geotechnical and hydrogeological studies. The methodology entails a review of cored hole data and use of twin holes to assess the typical geochemical and geophysical signatures of units identified. Improved interpretation of reverse circulation drill-holes has resulted in the development of detailed 3D engineering geological models, which have improved the understanding of geological variability and engineering properties for geotechnical and hydrogeological studies.

Comparison of a logistic regression and Naïve Bayes classifier in landslide susceptibility assessments: The influence of models complexity and training dataset size

The main objective of the present study was to compare the performance of a classifier that implements the Logistic Regression and a classifier that employs a Naïve Bayes algorithm in landslide susceptibility assessments. The study provides an evaluation concerning the influence of model's complexity and the size of the training data, while it identifies the most accurate and reliable classifier.The comparison of the two classifiers was based on the assessment of a database containing 116 sites located at the mountains of Epirus, Greece, where serious landslides events have been encountered. The sites are classified into two categories, non-landslide and landslide areas. The identification of those areas was established by analysing airborne imagery, extensive field investigation and the examination of previous research studies. The geo-environmental conditions in those locations where analyzed in regard with their susceptibility to slide. In particular, seven variables where analyzed: engineering geological units, slope angle, slope aspect, mean annual rainfall, distance from river network, distance from tectonic features and distance from road network.Multicollinearity analysis and feature selection was implemented in order to estimate the conditional independence among the variables and to rank the variables according to their significance in estimating landslide susceptibility. By the above processes the construction of nine different datasets was accomplished. Further partition allowed creating subsets of training and validating data from the original 116 sites. Each dataset was characterized by the number of the variables used and the size of the training datasets.The comparison and validation of the outcomes of each model was achieved using statistical evaluation measures, the receiving operating characteristic and the area under the success and predictive rate curves. The results indicated that model's complexity and the size of the training dataset influence the accuracy and the predictive power of the models concerning landslide susceptibility. In particular, the most accurate model with high predictive power was the eighth model (five variables and 92 training data), with the Naïve Bayes classifier having a slightly higher overall performance and accuracy than the Logistic Regression classifier, 87.50% and 82.61% on the validation datasets, respectively. The highest area under the curve was achieved by the Naïve Bayes classifier for both the training and validating datasets (0.875 and 0.806 respectively) while the Logistic Regression classifier achieved a lower AUC values for the training and validating datasets (0.844 and 0.711, respectively). When limited data are available it seems that more accurate and reliable results could be obtained by generative classifiers, like Naïve Bayes classifiers. Overall, landslide susceptibility assessments could serve as a useful tool for the local and national authorities, in order to evaluate strategies to prevent and mitigate the adverse impacts of landslide events.

Engineering geological conditions of the Holocene sediments of Anzali area, South Caspian Coast, North Iran

A broad assessment of the geological, sedimentological, and geotechnical characteristics of the coastal Holocene sediments of Anzali Area (North Iran) was made to provide a useful guide for development, planning, and construction. Based on the sedimentological and geotechnical properties of the sediments, three engineering geological units as Upper Sandy Zone (USZ), Middle Clayey Zone (MCZ), and Lower Sandy Zone (LSZ) were identified and introduced in the form of an engineering geological model. Then the engineering geological characteristics of the units of the model were analyzed and the main engineering geological problems associated with the deposits of each unit were identified. The results showed that USZ has high liquefaction potential, low bearing capacity, settlement susceptibility, and excavation problem; MCZ has low-bearing capacity as well as high settlement susceptibility and excavation problem; and LSZ has good geotechnical properties, then it poses few problems.

Geomorphological site classification for the Fujian province

Geomorphological classification of the Fujian province was done based on remote-sensing imaging, digital elevation maps, and slope gradient data acquired by ArcGIS 9.2. The engineering geological units in the Fujian province were divided into five types by the geomorphologic shape and genesis. The relationship among geomorphological type, engineering geological unit, and site category was determined using engineering geological data and site category data. Then, after making a preliminary site classification adjusted by drill hole data, the site was classified into four types: I0, I1, II, and III according to site classification standards of equivalent shear-wave velocity and overburden thickness. The results showed that the site categories in the Fujian province mainly consist of type II, which accounts for 85.26 % of the land area. The percentage of I0 was the smallest, which accounts for only 2.44 % of the total area.

Evaluation of TBM Utilization Using Rock Mass Rating System: A Case Study of Karaj-Tehran Water Conveyance Tunnel (Lots 1 and 2)

Successful application of a TBM in a project requires investigating both the ground conditions and the machine and backup system design features. Prediction of the machine performance is very important as it has a big effect on the duration of the project and the costs. In this respect, both penetration rate and advance rate must be estimated. Utilization factor, which depends on the type of operation, management, maintenance, geological conditions, mucking delays and other downtimes, correlates the advance rate and penetration rate. Adverse rock mass conditions such as mixed face condition, water problem and instability of rock have a great role in TBM downtimes and reduce the machine utilization considerably. Based on detailed engineering geological reports and maps and daily site reports taken from Karaj-Tehran Water Conveyance Tunnel ( Lots 1 and 2), this paper evaluates, main rock mass properties utilized for the estimation of TBM performance and discusses their effect on the machine utilization. . More specifically it uses the developed database also contains daily boring time, different rock mass related downtimes, daily advance and length of bored tunnel in each engineering geological units. It is concluded that the percentage of the rock mass related downtimes can be estimated via RMR within reliable coefficient of determination.

Engineering geological map of the Chiavari city area (Liguria, Italy)

An engineering geological map at a scale of 1:10,000 of the Chiavari city area (Northern Italy) – a major tourist and economic attraction of the Ligurian East Riviera – is presented in this paper. The municipality land shows an excellent geomorphological case-study of the well-known Ligurian coast: a floodplain, fairly wide and inhabited, formed by several floods of the two main rivers, a hill hinterland, reasonably inhabited, developed in marly limestones and sandy shales flysch and the coast – featuring cliffs and narrow pebbly beaches – deeply modified. This map was compiled by combining available geological data with a new engineering geomorphological field survey and including geotechnical data which were obtained from studies carried out for town planning and building purposes. On the basis of the critical review of the available lithostratigraphic data from drilling, as well as geotechnical and geophysical analyses carried out between 1981 and 2010 on the municipality land, an engineering geological map was compiled. Nine engineering geological units were established, based on their physical characterizations and geomechanical properties. This paper presents an example of geocartography that could be applied to urban land planning for housing and construction of technical works; it also represents the base for geological hazard evaluation.

Three-Dimensional Geological Modeling Based on Division of Engineering Geological Strata Units

Three-Dimensional Geological Modeling Based on Division of Engineering Geological Strata Units

Preliminary data for development of the engineering geological map of the city of Split (Croatia)

The city of Split has been developing continuously since the construction of the Diocletian Palace (287–305) to the present time. Detailed engineering geological investigations, with the recorded documents, have been performed since 1970. Further development and expansion of the city require an urban engineering geological map to be developed as a main prerequisite for the geotechnical and seismic zonation. In this paper a review of engineering geological conditions at the area of Split City (cca 25 km2) is given. Those conditions are interpreted on the basis of available data from geotechnical reports (about stratigraphical units, their lithological composition and physical and mechanical properties) and limited field survey. Zones with different ground conditions regarding rock properties are delineated in the form of lithological complex, engineering geological mapping units for medium-scale maps. The area of the city of Split, built of foraminifera limestones (E1,2), clayey glauconitic limestones ( $$ E_{2}^{1,2} $$ ), and flysch sediments (E2,3), is divided into five lithological complexes, which presents unique combination of individual lithological type for which it is possible to indicate general behavior of the whole. The paper also provides short review of other environmental conditions (active geomorphological processes, hydrological and hydrogeological conditions, as well as seismic conditions), which are intended as a guide to the sort of environmental data that could be collected by more detailed studies during the course of the zoning process.

Engineering geological data in support of municipal land use planning—a case study in Analândia, southeast Brazil

This paper presents a method for transforming the information of an engineering geological map into useful information for non-specialists involved in land-use planning. The method consists of classifying the engineering geological units in terms of land use capability and identifying the legal and the geologic restrictions that apply in the study area. Both informations are then superimposed over the land use and a conflict areas map is created. The analysis of these data leads to the identification of existing and forthcoming land use conflicts and enables the proposal of planning measures on a regional and local scale. The map for the regional planning was compiled at a 1:50,000 scale and encompasses the whole municipal land area where uses are mainly rural. The map for the local planning was compiled at a 1:10,000 scale and encompasses the urban area. Most of the classification and operations on maps used spatial analyst tools available in the Geographical Information System. The regional studies showed that the greater part of Analândia’s territory presents appropriate land uses. The local-scale studies indicate that the majority of the densely occupied urban areas are in suitable land. Although the situation is in general positive, municipal policies should address the identified and expected land use conflicts, so that it can be further improved.

Engineering geological map of the urban area of Kastoria, NW Greece

In the present work, the engineering geological conditions of the urban area of Kastoria were examined. More specifically a geotechnical assessment of subsoil and rock outcrops within a minimum depth of 20 m bellow surface is made, for urban planning purposes. Landslide potential of the studied area including mainly rock falls and ground subsidence was also evaluated. Eleven engineering geological units were identified and mapped at 1:5.000 scale, which constitute the foundation ground of the old Kastoria town, as well as of its new areas of built-up extension. The identified ground units consist of six soil and five rock types. Soil units comprise one fill formation of variable composition and consistency with a ranging thickness between 2 m and 6 m and five loose to cohesive deposits, Holocene to Upper Pliocene in age, with high variation in grain size, density and plasticity factors. Rock lithologies range from highly to moderately weathered, closely fractured serpentinites and schists to fresh, widely fractured limestones. The old city of Kastoria is founded mainly on stable rocky ground and does not show any remarkable geotechnical problems. However, the need of built-up extension however and improvement of infrastructures, led to configurations of the marshy areas and to the use of foundation ground with poor mechanical properties, which locally need a special treatment to become stable.

Adjustment of maximum ratings of RMR parameters using a canonical correlation analysis

The most widely used and the best known rock mass classification, the RMR system doesn't represent local geological characteristics enough. The canonical correlation analysis was carried out with 3 kinds of face mapping data obtained from granite, sedimentary rock and phyllite in order to clarify a discrepancy between rock types. According to analysis results, as a type of rocks changes, RMR factors have different influences on the total rating of RMR. Based on the result, this study shows there is necessity to adjust rating ranges of each of RMR parameters according to engineering geological units. (A) This paper was presented at Safety in the underground space - Proceedings of the ITA-AITES 2006 World Tunnel Congress and the 32nd ITA General Assembly, Seoul, Korea, 22-27 April 2006. For the covering abstract see ITRD E129148. “Reprinted with permission from Elsevier”.

Engineering-geological map of the wider Thessaloniki area, Greece

The preparation and compilation of a 1:10,000 scale engineering geological map of the wider Thessaloniki area is discussed. This map includes the range of values of the geomechanical characteristics of the 13 engineering geological units distinguished. Greater detail was available in the inhabited and industrial areas where many of the 1,300 boreholes studied had been drilled. Particular emphasis was given to the earth fill unit, which in places is up to 20 m thick. Some of the underlying Quaternary units are aquifers and severe pumping has resulted in both a lowering of the groundwater level and surface subsidence. The subsidence was most prominent in the Sindos–Kalohori–Axios River zone and required the construction of an embankment along the coast.