Engineering Geological Investigations Research Articles

Axial friction response of full-scale pipes in soft clays

The axial friction response of subsea pipelines in soft clays is a very important aspect for designers of subsea pipelines but the response is not well understood so far. There is a pressing need for the comprehension of the response. In this paper, model tests are performed using full-scale pipes coated with polyethylene (PE) to study the effects of the set-up period, the pipe diameter, the buried depth of the pipe, the shear strength of soft clays and the loading rate on the axial friction response of pipelines in soft clays. The variations of the axial friction coefficient are analyzed using the effective stress method based on model test results. The results show that the axial friction resistance increases with the increasing pipe diameter but the effect of the pipe diameter on the axial friction coefficient can be neglected. The ultimate axial resistance also increases with the increase of the buried depth of pipelines, the undrained shear strength of soft clays and the loading rate. The axial friction coefficient increases with the increasing loading rate. However, the axial friction coefficient decreases with the increasing buried depth. The method to determine the axial friction coefficient is developed by analyzing model test results, which considers the effects of the diameter, the buried depth, the undrained shear strength of soft clays and the loading rate. The study results not only extend the industry data base but also supply a basis to determine the axial friction coefficient of PE-coated pipes in soft clays for ocean engineering geological investigations.

Rockfall at the heritage site of the Tatlarin Underground City (Cappadocia, Turkey)

Cappadocia is one of the most important natural, historical and cultural heritages of Turkey. The region is seriously threatened by different instability problems, and several locations were accordingly closed to visit, mainly because of rockfalls. The aim of current study is to investigate the rockfall hazard potential near the Tatlarin Underground City. For this purpose, an extensive engineering geological investigation was performed and complemented with a set of rockfall simulations performed by means of the 3D numerical model HY-STONE. The investigation included: (1) mapping of the lithological units (tuffs and overlying basalts, talus deposits) and of unstable blocks along the cliff; (2) rock mass geomechanics and kinematic analysis of block stability; and (3) laboratory testing of tuff and basalt. These allowed to show that the instabilities are mainly controlled by different durability of tuffs and basalts. The weakness of tuffs facilitates a progressive undercutting of the basalt layer, the opening of subvertical joints and the consequent movement of large basaltic blocks. Two future potential rockfall scenarios have been produced by 3D rockfall modelling for hazard zonation and for suggesting risk management strategies. Model parameters were calibrated by back-analysis of both historical events and field tests. Different sets of parameters have been calibrated for different release volumes to consider different degrees of interaction with slope material of different size. The effect of roughness of the topography was investigated in terms of trajectories and lateral dispersion of blocks and its consequences on hazard zonation and risk management actions.

Constantly operating geoinformation system for geoenvironment as a tool for pre-project investigations in city infrastructure development (on the example of moscow)

The concept of a geoinformation system for urban geoenvironment is concerned. Geological data is necessary for the sustainable development of city infrastructure. The municipal departments should use geological and environmental information for perspective planning, selecting the location for important infrastructure objects, solving ecologycal problems, and in decision making. The concept includes a preliminary list of system’s users, their informational needs, main functionalities, methodical approaches to the system design and development. Geological data must contain source documents from geological archives “as is” and geodata based on its interpretation for various tasks. These data must be checked carefully and updated with new engineering-geological investigations. Geoinformation system must integrate various geological, engineering-geological, hydrogeological, and environmental data. Sophisticated procedures must be provided to check complicated logical dependences in the system database and to analyze contradictions between source documents. 3D modeling is an adequate language for presenting geological data, therefore, the considered system must include 3D models of various scales. In the suggested concept 3D modeling is considered as a tool for investigations, not only for presentations. The end users should have possibilities to get results of their queries in various formats: tables, geological and thematic maps, geological cross-sections, 2D and 3D grids as source data for mathematical modeling, etc. In conclusion, the paper briefly describes IEG RAS activities in GIS technologies for geological cartography and 3D modeling.

RMR岩体质量稳定性分级方法在塔尔德布拉克左岸金矿巷道支护中的应用

岩体稳定性评价是巷道开挖和支护设计时的一项基本任务。本文基于岩体质量分类方法，通过对塔尔德布拉克左岸金矿的工程地质调查，结合矿岩物理力学参数，对矿石和围岩进行了稳定性分级，并根据矿岩稳定性分级提出了针对性支护方案，并取得了较好支护效果。 Stability evaluation of rock masses is a basic procedure for the design of various underground excavations and support measures. In this paper, engineering geological investigation into country rock and ore body around excavations was extensively carried out; and samples were collected to test their physic-mechanical parameters in laboratory. Then, engineering rock masses in question were classified based on rock mass rating (RMR) and accordingly ground support measures were also proposed with a good effect obtained.

Role of engineering geology investigations in deep excavations

Role of engineering geology investigations in deep excavations

Assessment of engineering geological design parameters for Kandil (CFRD) Dam, Kahramanmaras-Turkey

This paper discusses the engineering geological investigations, engineering properties of the rock mass at the dam site, and construction materials for the dam embankment. Kandil Dam is located in Kahramanmaras southeastern Turkey. It is used for energy production and water storage for irrigation. Engineering geological mapping, analysis of the discontinuity system, drilling, trial pitting, Lugeon water pressure tests and laboratory tests were undertaken. As a result of site survey and test results, three pervious and one impervious material quarries were identified. Rock mass classifications were performed in accordance with Rock Mass Rating (RMR) systems for the diversion tunnel. Bedrock in the foundation consists of amphibolites rated by the RMR method as “good rock”. Based on evaluation of the site and laboratory data, two different quarries were selected for embankment fill materials. In addition, one impervious material quarry was located for cofferdam construction.

The Relationship of Physical Property Indicators and Clay Soil Structural Strength of Tomsk Oblast Territory

The article deals with the characteristic of initial condition in fine-grained soils - its structural strength - pstr. Estimation and measurement of this factor at soil testing are of primary importance for defining its physical and mechanical properties as well as for subsequent calculation of foundation settlements that is insufficiently covered in Code of practice, national standard and inefficiently applicable in practice of engineering geological investigations. The article reveals the relationship between soil physical property, its occurrence depth, which will make possible to forecast pstr over the given territory.

INFLUENCE OF GEOLOGICAL CONDITION TOWARDS SLOPE STABILITY ON LANDSLIDE: CASE STUDY IN TENGKLIK VILLAGE, TAWANGMANGU DISTRICT, KARANGANYAR REGENCY, CENTRAL JAVA PROVINCE, INDONESIA

A rain-induced landslide has occured in Guyon Village, Tengklik Tawangmangu District Karanganyar Regency, Central Java Province, Indonesia on February 2009. The movement was initiated by crack occurrence, 30 cm in depth and 2 meter in length. Such crack continuously developed in depth, extention and numbers, until then it resulted in land subsidence up to 260 cm in depth. Accordingly, ten houses were damaged and ten of families must be evacuated. This subsidence is very potential to further grow and create more consequences for human life and houses / land damage. Therefore, this research is carried out to understand the influence of geological factors and rainfall to the landslide phenomena. This research conducted engineering geology investigation such as mapping, drilling, insitu test, XRD test, soil mechanic test and slope stability analysis by limit equilibrium method i.e. Seep/W and Slope/W. By those research activities, the cause and mechanism of landslide can be understood. Rainfall characteristics which triggered such landslide can also be identified.
 
 Based on those investigations, it is found that the landslide occurred in slow rate sliding (creep) due to the control of slope stratigraphy conditions and gentle slope inclination, which is induced by rainfall. Stratigraphy condition that plays important role in landslide mechanism are the permeable layers consisted of sandy silt (shear strength 12 kPa) and silty sandstone (shear strength 18 kPa) overlaid above impermeable andesite breccia (shear strength 104 kPa). Undulating slope may induce landslide in creep rotational type. Based on slope stability simulation, it is known that rainfall triggered landslide is rainfall 20 mm/ day average precipitation in 55 days and rainfall 20 mm/ day average precipitation in 49 days followed by one day with 178 mm/ day average precipitation.
 
 Keywords: Landslides, slope stability

DETERMINATION OF NUCLEAR POWER PLANT SITE IN WEST BANGKA BASED ON ROCK MASS RATING AND GEOLOGICAL STRENGTH INDEX

Indonesian government through the National Atomic Energy Agency has planned to build a nuclear power plant. One of the proposed sites is in West Bangka Regency, Bangka Belitung Archipelago Province. The engineering geology of this area is, however, not fully understood and requires further investigations. Engineering geology investigations were carried out by assessing the rock mass quality and bearing capacity based on field observation and drilling data. The assessment was conducted using Rock Mass Rating (RMR) and Geological Strength Index (GSI) classification. The rock mass in the study area was divided into four units, namely Units of Sandstone, Granite, Mudstone and Pebbly Sandstone. The RMR and GSI values in the study area are influenced by the parameters of discontinuity space density, the slope of discontinuity orientation, grade of weathering and groundwater conditions. The assessment shows that the Granite Unit has the best quality which is shown by the average RMR value of 53 and GSI value of 66. Based on the average RMR value, the Granite Unit is estimated to have cohesion value between 0.2 and 0.3 MPa, friction angle between 25° and 35°, and allowable bearing pressure between 280 and 135 T/m2. Based on the GSI value, the Granite Unit is estimated to have uniaxial compressive strength value between 1.0465 and 183.8 MPa, tensile strength between (-0.0122) and (-5.2625) MPa, rock mass strength values between 24.5244 and 220.351 MPa, and modulus of deformation within a range of 1.73–86.68 GPa. The Granite Unit is considered to be the most appropriate location for the nuclear power plants. Keywords: Nuclear power plant foundation, geological strength index, rock mass rating, rock mass quality

DETERMINATION OF NUCLEAR POWER PLANT SITE IN WEST BANGKA BASED ON ROCK MASS RATING AND GEOLOGICAL STRENGTH INDEX

Indonesian government through the NationalAtomic Energy Agency has planned to build anuclear power plant. One of the proposed sitesis in West Bangka Regency, Bangka BelitungArchipelago Province. The engineering geologyof this area is, however, not fully understood andrequires further investigations. Engineering geology investigations were carried out by assessing therock mass quality and bearing capacity based onfield observation and drilling data. The assessmentwas conducted using Rock Mass Rating (RMR)and Geological Strength Index (GSI) classifications.The rock masses in the study area were dividedinto four units, namely units of sandstone, granite,mudstone and pebbly sandstone. The RMR andGSI values in the study area were influenced by theparameters of discontinuity space density, the slopeof discontinuity orientation, grade of weatheringand groundwater conditions. The assessment showsthat the granite unit had the best quality which wasshown by a 53 average RMR value and 66 GSIvalue. Based on the average RMR value, the graniteunit was estimated to have cohesion value between0.2 and 0.3 MPa, friction angle between 25° and35°, and allowable bearing pressure between 280and 135 T/m2. Based on the GSI value, the graniteunit was estimated to have uniaxial compressivestrength value between 1.0465 and 183.8 MPa, ten-sile strength between (-0.0122) and (-5.2625) MPa,rock mass strength values between 24.5244 and220.351 MPa, and modulus of deformation withina range of 1.73 - 86.68 GPa. The Granite Unit wasconsidered to be the most appropriate location forthe nuclear power plants.

基于ADINA的露天煤矿高边坡变形及稳定性分析

为掌握露天煤矿高边坡变形规律及应力分布特征，基于现场工程地质调绘分析，运用ADINA分析了宝日希勒露天煤矿边坡的应力分布及变形破坏机理，并根据强度折减法理论对边坡稳定性进行计算分析，结果表明：边坡可能沿软弱夹层滑动破坏，且破坏模式为顺层–后缘穿层滑动(折线滑动)。 In order to grasp the opencast coal mine high slope deformation law and stress distribution cha-racteristics, through the analysis of the engineering geological investigation, the paper analyzes the stress distribution and the deformation failure mechanism of the slope of Baorixile open pit coal mine based on ADINA. Slope stability is analyzed based on the strength reduction theory. The results show that the slope may be sliding failure along the weak interlayer and that the failure mode is bedding-trailing edge wear layer sliding (fold line sliding).

Some Remarks on Single-Channel and Multi-Channel Seismic in Offshore Engineering Geological Exploration

Single-channel and multi-channel seismic exploration have become two important geophysical methods in offshore engineering geological investigation. Both of the two methods can present high sensitivity and high resolution information about the strata under the seafloor. However, the single-channel seismic prospecting method has some limitations in high resolution engineering surveys. For example, (1) When the depth of water is relatively shallow, the system cannot get zero offset profile; (2) The reflective events will be distorted if the terrain of the seafloor is complex, and thus make the interpretation much more difficult; (3) We cannot remove the influence of the complex multiples in single-channel seismic data processing; (4) We cannot get the lithological and physical properties directly using single-channel seismic method; and, (5) The spatial resolution of single-channel is also lower than that of multi-channel seismic method. In this paper, we presented some examples, and the above problems have been discussed to compare the two methods. All those can give a good guide for selecting appropriate exploration methods.

GEOMECHANICKÉ VLASTNOSTI NEOGENNÍCH JÍLŮ NA ÚZEMÍ MĚSTA BRNA

Neogene clays in Brno area are formations belonging to the Carpathian Foredeep Basin. They form common foundation soil in this strongly urbanized area. Due to their specific mechanical characteristics and a large spreaded area in Brno a detailed study of the geomechanical properties of Neogene clays has practical importance for engineering geology and geotechnics. There are compared analyzed data of physical and mechanical properties from 81 engineering-geological reports at the Brno agglomeration (452 samples of Neogene clays from 180 bores). There are presented the anomalous, distant values, arithmetic average and mode of the Neogene clays. On the basis of assumed data from various geological-engineering reports are defined typical characteristics of these soils. Neogene clays are fine-grained cohesive soils. In terms of ČSN EN ISO 14688-1, 14688-2 and UCSC classification these are classified mainly as clay or silt with high, very high or extremely high plasticity. It is usually with high plasticity index, stiff and very stiff consistence and with medium and high undrained shear strength. Low values of cohesion could be related to soil damaged by landslide movements. Due to its unfavourable properties, Neogene clays refer to partly suitable environment for shallow strip-foundations mainly due to the possibilities of volume changes in the subground. For all projection of foundations, there should be paid special attention to good engineering-geological investigation at real site.

THE RESULTS OF THE DEFECT PLACES INVESTIGATION OF DONETSK RAILWAY ROAD BED BY GROUND PENETRATING RADAR COMPLEX

Purpose. Defective places definition of road bed at ground penetrating radar is examined. Methodology. For achievement of this goal the experimental research on ground penetrating radar inspection of road bed defective places of the Donetsk Railway, which are caused by a complex of various reasons of geotechnical and constructive character, were conducted. Findings. According to these diagnostic results of road bed on the three districts of the Donetsk Railway is revealed the main causes which lead to the defects appearance, deformities and injuries in it, there is abuse of process parameters and modify its physic mechanical soil properties of natural and technology-related factors. As it is established, the use of ground penetrating radar of series “Losa” on the railways of Ukraine allows searching ballast tank in the body of road bed, defining damp places in soil road bed and foundations, to find arrangement of foreign matter in the soil road bed and work search heterogeneity and places weakening soil. In addition, the use of ground penetrating radar provides rapid detection of defects, deformation and damage of railway track, especially in areas the most dangerous for rolling stock that creates the high level security at the main and auxiliary lines of Ukrzaliznytsia. In conducting the research was justified the high level of reliability and performance with autonomous use of ground penetrating radar. Originality. In modern conditions of defects determination, deformations and damages by traditional methods with application of engineering-geological investigations, it is impossible in connection with their insufficient efficiency. Therefore the using of highly effective methodology of expeditious tool identification of defective places allows reducing significantly the periods of repair of a railway track which is very important for introduction of the highspeed movement on the Ukrainian Railways. Practical value. On the basis of the executed investigations the main actions for defects elimination, deformations and damages which consist in the device of counter dams, the draining sections, the augercast and augured piles are offered.

Monitoring and analysis of burning in coal tailing dumps: a case study from the Czech Republic

The tailings are significant geological environments in mining and industrial regions. They represent special engineering-geological zones of anthropogenic sediments that require specific engineering-geological investigation. In particular, it is important to examine the sites in detail with regard to their potential heterogeneity. The article deals with an important engineering-geological issue of burning in coal mine and coal tailing dumps. A case study was implemented in a tailing dump in Heřmanice located in Ostrava which is a major industrial city of the Czech Republic. In this urban agglomeration, anthropogenic sediments form 20 % of all foundation soils. Thermometric monitoring in Heřmanice detected a thermally active coal tailing dump with burning as deep as 9 m. The burning is predominantly related to the content of oxygen in the body of the tailing. It belongs to the limiting conditions of the pyrophoric and consequently self-sustained burning. Other factors are sufficient contents and quality of coal mass and capacity to accumulate thermal energy of exothermal reactions. Dynamics of changes in the burning processes were identified in dependence on time, depth and distribution. There was a considerable heterogeneity of thermal activity as for all parameters, and changes were observed from the point of view of time. Considering the depth, burning gradually spread deeper. However, in the depth of 12 m, no significant thermal activity was observed within the overall studied locality. It may be stated that thermal activity is observed as much as 40 % of the studied area. Directionally, there was a progression of the process from west to east. The identified facts may be applied in final designed levels of coal tailing dumps where observational experiences identified intense cooling up to the height of 5 m preventing higher stages of self-ignition process (best situation). Tailing dumps from 5 to 12 m may already be thermally active (meeting other boundary conditions), and in tailing dumps over 12 m, it is clear that there is no thermal activity below 12 m.

Optimization of construction scheme and supporting technology for HJS soft rock tunnel

For a soft rock tunnel under high stress in jointed and swell soft rock (HJS), two construction schemes pilot-tunneling enlarging excavation and step-by-step excavation were optimized using FLAC2D, and the deformation effects of the two construction schemes were verified by field tests. Based on engineering geological investigation and mechanical analysis of large deformations, the complex deformation mechanisms of stress expansion and structural deformation of the soft rock tunnel were confirmed, and support countermeasures from the complex deformation mechanism converted to a single type were proposed, and the support parameters were optimized by field tests. These technologies were proved by engineering practice, which produced significant technical and economic benefits.

Instability Mechanism and Supporting Measure for Highway Tunnel with High Ground Stress and Soft Surrounding Rock

For the tunnel with high ground stress and soft surrounding rock, the deformation instability is the high frequency and great harm geological hazard. The supporting measure has become a important technique problem. This paper based on the Wuduxi tunnel, the characteristics of deformation and instability mechanism of surrounding rock and supporting structure are analyzed by means of the engineering geological investigation, theoretical analysis and field monitoring. The supporting measure include that using the steel floral tube to back up sidewall, adding support arch and filling foamed concrete, grouting reinforcement in basement. Finally, we use the field monitoring to check the supporting effect. The result shows that the supporting measure could achieve the desired treat effect and it has reference meaning to similar engineering.

Engineering geological and geotechnical investigations along the head race tunnel in Teesta Stage-III hydroelectric project, India

An investigation of the engineering geological properties and geotechnical parameters of rock masses along a horseshoe-shaped head race tunnel (HRT) in the Teesta Stage-III hydroelectric project, Sikkim, India, was carried out to analyze the rock mass properties for optimum support system. The empirical methods, field tests and numerical modeling were employed to determine rock mass properties. Several empirical equations and statistical analysis were performed to obtain the rational and reasonable results. The tunnel passes through different geological formations and critical zones. The field investigations indicate the presence of five joint sets, which contribute towards the development of unforeseen wedges along the tunnel alignment. The attitudes of joints were measured by Brunton compass and analyzed with Dips v.5.1 software. The potential wedge block analysis and factor of safety (FS) were determined using Unwedge v.3.0 software. The rock mass classification, assessment of tunnel stability and necessary support types were carried out with Q, RMR and RMi systems as empirical tunnel support design methods. The numerical method (Phase2 v.6.0) was used to quantify plastic zone and squeezing potential of the tunnel. The installed support systems as per empirical methods were cross-checked by means of numerical modeling, field observations and engineering judgments. According to the results from different methods, 3.0–4.4m rock bolts, shotcrete 0.1–0.15m, wire mesh and final concrete lining were proposed. It was observed that the plastic and deformed zones surrounding the excavation area got appreciably reduced after the recommended support installation.

BEARING PROFESSOR GU DEZHENS INSTRUCTION IN MIND,PUTTING PRACTICE IN FIRST PLACE AND PROMOTING ENGINEERING GEOLOGY AND GEOTECHNICAL ENGINEERING REACHING THE SAME GOAL BY DIFFERENT ROUTS

Taking the engineering geological investigation and exploration of rocky foundation soil and design and construction of foundation structure of Wuhan Changjiang River Great Bridge completed under professor Gu's lead and guidence for an example,this paper presents specifically and vividly that the first and the most important one among Mr. Gu's academic thoughts is attaching great importance to practice. To put in a nutshell,this thought plays great attention to investigation and exploration of engineering geology during the earlier stage of an engineering project. Then further verify and correct the achivements in the earlier work,closely combine the work with geotechnical engineering and,finally ensure safe and economical completion of those engineering projects,geological engineering project for the purpose of control and presentation of geological disasters and/or the specifical geotechnical engineering project.

Risk Assessment of Debris Flow Based on Multi-Objective Fuzzy Pattern Recognition Method in Mountain Highway Construction

It is inevitable that road routes cross the valley landforms in the construction of mountain road, and the debris flow risk assessment is one of the important basis works of engineering geological investigation. This paper presents the evaluation indexes and the classification standards of the danger evaluation based on the surveying data of road and analysis of the developing characteristic, formation conditions and influent factors of the debris flow in mountain highway construction area, Zhangjiakou city. With the multi-objective fuzzy pattern recognition method, the evaluation model is also established. With this model, the 15 debris flow valleys in the construction area are evaluated. The result is consistent with the field surveying result, which proves that the model represented by this paper is feasible and effective, and the results can reflect the actual situation. Thus, the multi-objective fuzzy pattern recognition method can be one of the methods to evaluate the danger grade of the debris flow.