Geological and Geotechnical Engineering

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.

This study aims to account for the petrogenesis and mineralization of pegmatites around the Wowyen area, northcentral basement complex,Nigeria. Field studies, petrography and whole rock geochemistry (Major oxides were estimated by X-Ray Fluorescence while the trace elements were estimated by Inductively Coupled Plasma Mass Spectrometry) where the methods adopted. The pegmatites around Wowyen area are emplaced in the remobilized belt of the Nigerian Basement complex. They are predominantly complex pegmatites (rare-metal pegmatites) which are intruded in the biotite-muscovite gneiss while the simple pegmatites intruded more in the migmatitic banded gneiss. The major components of the complex pegmatites are quartz, albite and muscovite and tourmaline.The accessory constituents are garnet; ilmenites; cassiterite-columbitetantalite oxides in contrast to quartz, microcline and biotite of the simple pegmatites. The complex pegmatites show higher peraluminous than the simple pegmatites, how...

The stability graph method of stope design is one of the most widely used methods of stability assessments of stopes in underground polymetallic mines. The primary objective of this work is to introduce a new stability chart, which includes all relevant case histories, and to exclude parameters with uncertainties in the determination of stability number. The modified stability number was used to achieve this goal, and the Extended Mathews database was recalculated and compared with the new stability graph. In this study, a new refined Consolidated stability graph was developed by excluding the entry mining methods data from the Extended graph data, and only the non-entry methods data was used. The applicability of the proposed Consolidated stability chart was demonstrated by an open stope example. The stability for each stope surface was evaluated by a probabilistic approach employing a logistic regression model and the developed Consolidated stability chart. Comparing the stability...

Abstract

Administratively the research area is located in Samigaluh District, Kulon Progo Regency, Special Province of Yogyakarta, precisely at the coordinates (UTM-WGS84-Zona 49S) 404090 mT to 412090 mT and 9147980 mU to 9151980 mU. The purpose of the research is to find out the characteristics and zones of vulnerability of soil movements that are influenced by the physical conditions of the research area. The research method used is deterministic method (SNI 8291: 2016). Identification of the vulnerability zone of land movement in Samigaluh district was carried out by analyzing the data in the form of overlaying slope parameter maps, geology, geological structure, and land use using geographic information systems (GIS). Data collection is done both primary and secondary data. Primary data includes the location of soil movements, dimensions of ground motion, geological conditions, morphological conditions, hydrological conditions and geotechnical soil. While secondary data includes geological maps, slope maps, land use maps, rainfall maps, and DEM data. The type of ground movement from the study is divided into 3, namely rock topple, nendatan (slump), and earth flow. The results showed that Samigaluh district had three levels of vulnerability to land movements, namely, low, medium and high. Most landslide locations are in areas with moderate to high levels of land movement vulnerability such as in Purwoharjo Village, Sidoharjo Village, Pagerharjo Village, and Ngargosari Village. Analysis of classification results shows that the trigger factors for the landslide movement are strongly influenced by the slope. Soil movements occur in areas with land use with little vegetation, steep slopes to steep, and in the constituent lithology of Tertiary volcanic products.
Keyword : GIS, Mass Movement, Samigaluh,Susceptibility

Ultimate capacity of large diameter bored piles is usually determined from pile loading tests as recommended by several international codes and foundation design standards. However, loading of this type of piles till achieving apparent failure is practically seldom. In this paper, numerical analyses are carried out to simulate load test of a large diameter bored pile performed at the location of Alzey highway bridge project (Germany). Test results of pile load settlement relationship till failure as well as results of the base and shaft resistances are available. Apparent failure was indicated in this test by the significant increase of the induced settlement during the last load increment applied on the pile head. Measurements of this pile load test are used to assess the quality of the numerical models investigated. Three different material soil models are implemented in the analyses: Mohr coulomb (MC), Soft soil (SS), and Modified Mohr coulomb (MMC). Very good agreement is obtain...

The present study investigates the use of natural pozzolana combined with lime for ground improvement applications. Laboratory tests were undertaken to study the effect of natural pozzolana, lime or a combination of both on the physical and the mechanical characteristics of cohesive soils. Natural pozzolana, lime and natural pozzolana-lime were added to two cohesive soils at ranges of 0–20 and 0–8%, respectively. Consistency, compaction, undrained traxial shear and unconfined compressive strength tests were performed on untreated and treated soil samples to assess the physical and mechanical characteristics of the soil. Treated samples were cured for 1, 7, 28 and 90 days. The results show that the cohesive soils can be successfully stabilized by combining natural pozzolana and lime.

O’Kelly, B. C. (2022) Discussion of “Advancement in estimation of undrained shear strength through fall cone tests” by Abhishek Ghosh Dastider, Santiram Chatterjee, and Prasenjit Basu. Journal of Geotechnical and Geoenvironmental Engineering 148(6): 07022005, https://doi.org/10.1061/(ASCE)GT.1943-5606.0002807

This note shows a study on the seismic passive earth pressure behind a non-vertical cantilever retaining wall using pseudo-dynamic approach. A composite failure surface comprising of an arc of the logarithmic spiral near the wall and a straight line in the planar shear zone near the ground, has been considered behind the retaining wall. The effects of soil friction angle, wall inclination, wall friction angle, amplification of vibration, horizontal and vertical earthquake acceleration on the passive earth pressure have been explored in this study. The results available in the literature for passive pressure, on the basis of pseudo-static analysis are found to predict the passive resistance on the conservative side and the assumption of a planar failure surface is found to overestimate the passive resistance for higher wall friction. An attempt has been made in the present study to overcome both the limitations simultaneously. The present results are compared with the existing values in the literature and found a reasonable match among the values.

The study of geological problems related to the presence of underground cavities, in an urbanized environment like the city of Palermo, is a theme that had and still has strong implications for the development of the city. Starting from the origins to the present day, the process of human land with urban development over the rivers Kemonia and Papireto of Palermo, supported by economic, technological and social progress, has contributed to the growth of the city, but has also altered the physical environment and a deterioration in the balance, causing him to cause those conditions of instability, which will be the subject of study. The work has involved some type of underground cavities, such as bomb shelters, the culverts for hydraulic defense of the city and the anthropogenic cavities l.s. (underground mines, qnat, underground tombs, etc..). Through the pages of the newspaper "Giornale di Sicilia" survey was conducted a chronological historical survey on subsidence occurred on the beginning of last century until 2009, and we made use of the collaboration of the Prediction and Prevention task force of the Civil Protection Office and Building unsafe of the town of Palermo. Were shown the geological characteristics of the areas affected by subsidence, that the analysis had a practical acknowledgment of the situation, we generated a database GIS regarding the phenomenology of the affected, and has produced a map of areas affected by the phenomena of sinkholes, in scale 1:10.000, which were limited to areas subject to this phenomenon and located the places where they occurred.

This paper presents an empirical model for estimating rock mass hydraulic conductivity of fractured Hawkesbury Sandstone in the Sydney basin. The hydraulic conductivity of a fractured crystalline rock mass can be a critical factor in tunnelling projects and dewatering designs. The Lugeon test (commonly known as the "packer test") is a common test used to estimate the in-situ permeability of a rock mass. The Packer test is carried out over a specific length (typically 3-6 m) within a borehole to reduce the range of variation of the affecting parameters. To construct a detailed profile of hydraulic conductivity through the rock mass a relatively large number of Packer tests are often required which can be costly and time consuming. The new rock mass classification system called the "HC system" was proposed by Hsu et al. (2011). The HC-system assists with the hydraulic modelling of a rock mass and is based on 4 parameters which can be readily assessed from borehole logs and borehole Televiewer data, namely Rock Quality Designation (RQD), Depth Index (DI), Gouge Content Designation (GCD) and Lithology Permeability Index (LPI). A modified new rock mass classification system called the "HC-system" or HC model has been specifically developed for Hawkesbury Sandstone in the Sydney basin. Regression analysis was conducted to assess the correlation between the calculated HC value (using the HC model) and the corresponding hydraulic conductivity from the in-situ packer tests. To confirm the feasibility of the proposed empirical HC model, the model was subsequently used to estimate the hydraulic conductivity of similar Hawkesbury Sandstone boreholes from a range of projects that also have corresponding Packer test data for comparison. This empirical HC model may assist with two important hydrogeological applications. The first application is to estimate hydraulic conductivity of fractured sandstone of similar geological set up based on HC-values. By using this approach, hydraulic conductivity data in a given site can be estimated from borehole data, which increases the reliability and confidence of the packer testing. Secondly, for in-situ aquifer tests the HC-system is a valuable new rock mass classification system for estimating the degree of permeability of a borehole. The results obtained confirm the validity and flexibility of the empirical approach to handle cases of onshore and offshore data sets, in relation to data acquisition and data reduction (optimisation).

Keywords:
Lugeon, hydraulic conductivity, Rock Quality Designation (RQD), Depth Index (DI), Gouge Content Designation (GCD), Lithology Permeability Index (LPI), Regression analysis.

For Citation:
Jembere D & Yihdego Y (2019) An empirical model to correlate rock mass classification and hydraulic conductivity, geotechnical engineering data acquisition and reduction perspective. In H. Khabbaz, A. Parsa, AHMK. Zaman & C. Rujikiatkamjorn., 2019 (eds.). INNOVATIONS IN GEOTECHNICAL CONSTRUCTION & DESIGN. Australian Geomechanics Society (AGS). PROCEEDINGS OF THE 2019 AGS SYMPOSIUM. Sydney, Australia. November 15 2019. Pages: 66-77.

URL:
https://australiangeomechanics.org/meetings/2019-sydney-symposium/

INNOVATIONS IN GEOTECHNICAL CONSTRUCTION & DESIGN. The Australian Geomechanics Society sponsored by Engineers, Australia & The Australasian Institute of Mining & Metallurgy (AusIMM)

Monitoring of strata control parameters and behaviour of a powered support was carried out during an experimental trial of a mechanized longwall sublevel caving face for exploitation of a 7.5 m thick coal seam. Field observations indicated that the requirement of support ...

The choice and dimensioning of the foundations are made according to the physical properties of the soil and the type of structure to be built. This research concerns the assessment of the KAMATANDA platform soil capacity, which has to support series of crushers and mechanical launders. Laboratory tests determined the physical properties (moist unit weight, dry unit weight, moisture content and particle size analysis) from soil samples taken at four different depths. In situ, we determined the mechanical properties of the soil by the dynamic cone penetrometer test. The soil of the KAMATANDA platform was the poorly graded sands by size classification. By doing the test, the moisture content, the moist unit weight and dry unit weight were increasing from 0 to 5 meters. The compactness was increasing when going deep but the rate of increase was getting less from 2.5 meters' depth. The soil presented the heterogeneities and the depth presenting much resistance to the penetration of the dynamic cone penetrometer was 2.4 meters. To avoid differential settlements, the embedding height was 1.2 meter. As per the minimum values, the dynamic resistance evaluated through the Dutch formula was 2.1MPa; however, the allowable bearing capacity, based on the dynamic resistance as per L'HERMINIER formula was 0.105MPa. We therefore noticed that, the resistance of KAMATANDA ground after dynamic cone penetrometer test relates to the compactness of the soil that grows according the depths.

Engineering failures are hard to define. They may form catastrophic disasters that are serious threats to public safety; yet, at other instances, they may be a shortcoming in the behavior or function of structures. A functional shortcoming, unforeseen and unplanned for, of an engineered element, may sometimes be considered a failure while at other times seen as tolerable or even advantageous. Engineers always regard failures as their greatest enemy; ironically, failures may be considered as their foremost teacher as well. Without failures, much of the current advances in design would not have been gained. Studying well-documented failures is important as the findings can be used to improve the designs and performance of structures. In this article, the different aspects related to failures and their prevention are explored. A conceptual model for the cost of failures is also presented. Additionally, some of the well-documented case histories of failures encompassing a wide range of geotechnical practices are highlighted and the learnt lessons are emphasized. It is demonstrated that failures may be substantially reduced by carrying out proper geotechnical site investigations, adopting flexible designs that incorporate observations during construction, applying strict site supervision, implementing geotechnical instrumentation programs and embracing risk management principles.

Nowadays groundwater has become a strategic resource for economic growth, poverty reduction, environmental sustainability, and climate change adaptation, especially in arid and semi-arid areas. Therefore, the estimation of groundwater recharge rate is necessary to develop the knowledge of groundwater availability for decision making and to device appropriate climate change adaptation. Various techniques are available to estimate groundwater recharge, however, most of these are lumped and/or empirical approaches which need available primary data. Fortunately, GIS and RS technologies with physically based hydrological models are freely available as alternative approach for such purposes. Groundwater recharge depends on distributed land use, soil texture, topography, slope, groundwater depth and meteorological condition. In this study, GIS with integration of physically based WetSpass model was applied to estimate groundwater recharge for Shinile sub-basin, Ethiopia. The study area covers 20,489km2 with minimum and maximum elevation of 231m and 2752m, respectively. The summer average actual evapotranspiration, surface runoff and recharge were estimated as 222.4mm, 15.4 and 88.5mm while the winter as 66mm, 1.68mm and 30.54mm, respectively. The results were also simulated in annual time step, in which resulted AET, surface runoff and groundwater recharge as 289mm(5.92BCM), 17.1mm (0.35BCM) and 120mm(2.44BCM), respectively. From simulated water balance components, AET is the main factor that the 68% of annual precipitation accounted to deplete.

Using high-quality hydraulic conductivity test results for compacted soil samples with widely different gradation characteristics, 14 commonly employed empirical correlations for estimating the permeability coefficient (k) were evaluated. Comparisons of measured and predicted k values indicated most predictions were within a margin of ±100%, although they could vary by up to 500% or more. Statistical analysis indicated that high coefficients of determination obtained for these datasets can be grossly misleading, since the data may have markedly high values of the standard error of the estimate. Grain size characteristics and void ratio were identified as the most sensitive input parameters for the models investigated. On this basis and using the results of hydraulic conductivity testing performed on 20 soil samples with very different gradations, a new prediction model that expressly considers both gradation and void ratio is proposed. Test results from an additional 16 sandy soil samples were used to validate the new model, which was found to produce a fairly good distribution of data points within 95% prediction intervals and an equitable spread about the unity line in a plot of predicted against measured k values. The experimental data were also analysed using the grading entropy framework.

Sabkha soils are salt-bearing formations that are formed in arid regions. In their in situ states the sabkha soils have high compressibility and low shear strength. These soils are also heterogeneous and their properties depend on the type and amount of salt present. Thus, these soils are not suitable for support of infrastructures without the risk of high settlement and/or bearing capacity failure. This paper investigates the possibility of using cement to improve the shear strength of sabkha soils for possible use as a foundation-bearing soil. The sabkha soil used in this study is a sandy sabkha obtained from the coastal plains at Al-Auzayba, Sultanate of Oman. Cement was added in percentages of 2.5, 5, 7.5 and 10%, by dry weight of soil. The soil-stabilizer mixers were allowed to cure for 7, 14 and 28 days. Laboratory tests such as compaction, unconfined compression, consolidated undrained triaxial and durability tests were performed to measure the engineering characteristics of the stabilized material. The results showed substantial improvements in the shear strength of the sabkha–cement mixtures and the mixtures are also durable with small weight loss after 12 wetting/drying cycles. Thus, cement can be used to improve the shear strength of sabkha soils. Furthermore, the effective stress path and the tress-strain relation of the sabkha–cement mixtures follow trends similar to those of cemented calcareous soils.

Anthropogenic activities on land resulted in landuse/landcover change including vegetation. Landuse changes play a role in the sustainability of refinery because of associated environmental effects. Moreover, there is growing societal concern about the spatial and temporal scales of some types of conversions, such as deforestation and urbanization. This paper determine the extent and rate of changes in landuse/landcover as a result of establishment of Kaduna Refinery and petrochemical company. The study employed the used of Remote Sensing and GIS techniques in acquiring and analysing the data respectively. The 1974 Landsat 4 Multispectral Scanner (MSS) 60m resolution, 1986 Landsat 5 Thematic Mapper (TM) 30m resolution, 1999 Enhanced Thematic Mapper Plus (ETM+) 30m resolution and 2018 Landsat 8 Operational Land Imager (OLI) 30m resolution images were used. A supervised Image classification method was used because of its high accuracy. This was carried out using ArcGIS 10.5 software. The built-up areas were constantly increasing, while vegetation and agricultural land were decreasing proportionally due to clearance to make room for the industry and settlements for staff and refinery attracted population. There is need for establishment of a programs that promote tree planting, must especially the exotics ones as they are the most threatened species in the area. The present agricultural land need to be preserve and new ones need to be open and expanded in order to improve the agricultural activities of the area.

The consolidation test is one of the most common laboratory tests in geotechnical investigations. It is mainly utilized to assess the clay operative constrained modulus, which is an essential parameter in the settlement calculations of foundations and embankments. Recently, the non-linear numerical modelling has become more common than ever in geotechnical engineering. The state-of-art advanced geotechnical analyses focus on consideration of the nonlinear variation of soil moduli with the stress and strain levels. One of the fundamental quantities in advanced non-linear geotechnical analyses is the small strain shear modulus. It is obtained by measuring the shear wave velocity using special tests or amendments to traditional tests. Such tests and/or amendments are generally much less common and more expensive than consolidation tests. In this paper, the shear wave velocity and small strain shear modulus of soft to firm clays are evaluated from results of consolidation tests. The site-specific constants that relate the void ratio to the shear wave velocities and small strain shear moduli are concluded from the water content measurements. The proposed approach is validated by analysing two well-reported clays (viz., Ariake and Singapore clays). The results of the analyses show the viability of the proposed approach as the estimated moduli are close to the values inferred from the field shear wave velocity measurements.

Hydraulic in situ measurement of rock mass permeability by packer (Lugeon) testing is an inherent and integral element of many engineering, hydrogeological and mining investigation. This paper describes and discusses geotechnical testing in the design process from a consulting practitioner’s perspective. This study focuses on the Packer testing planning, procedure, results & interpretation. Packer test system is an optimum method for obtaining values of hydraulic conductivity in wells that are difficult to analyse using conventional slug test systems. Packer tests are carried out to assess the variability of a borehole as it intersects various hydrogeological units. It gives vertical distribution of hydraulic properties and water quality in the aquifer and usually cheaper than a nest of wells and gives more continuous record and this knowledge can often be essential for a proper design. The role, objectives, types and interpretation of testing, limitations and recommended good practices as part of the geotechnical design process are outlined through the examination of test data from a case record.

Site investigation is essential prior to all construction activities of engineering structures for determining the suitability of the site for the construction of the proposed structure. The results from the site investigation gives us the information about the soil profile and the ground water table condition at the site. Various in-situ tests are carried out like Standard Penetration Test (SPT), Electrical Resistivity Technique (ERT), Vane Shear Test (VST), Plate Load Test (PLT), Pile Load Test, Flat Plate Dilatometer Test, Packer Test, Cone Penetration Test (CPT) and many others during the site exploration. The data and results obtained from these tests are essential in identifying the soil type, analyzing and the strength and deformation properties and parameters of soil as well as the ground water condition of the site. This paper intends to summarize the processes and various corrections that are involved in Standard Penetration Test (SPT) and its importance and implication in geotechnical analysis and site exploration. The tools and equipment in this test involved are cable percussion drilling rig, soil sampler (especially split spoon sampler), spirit level, boring machine and a hammer with few other miscellaneous. The soil sampler is pushed or penetrated into the ground by hammer of 63.5kg making it fall freely from a standard height of 750mm. The collected disturbed and undisturbed soil samples, hammer blows and energy are analyzed and interpreted to determine or more specifically to estimate the shear strength of soil, relative density and bearing strength of the soil at different depths. This test also helps in determining the aspects of soil which later can be improved by soil stabilizing or by any one or combination of various ground improvement techniques. In accordance of these interpretations, analysis and estimates, suitable foundation design and further construction work for the proposed structure are recommended.

Lateral load-deflection behaviour of single piles is often analysed in practice on the basis of methods of load-transfer P–Y curves. The paper is aimed at presenting the results of the interpretation of five full-scale horizontal loading tests of single instrumented piles in two sandy soils, in order to define the parameters of P–Y curves, namely the initial lateral reaction modulus and the lateral soil resistance, in correlation with the pressuremeter test parameters. P–Y curve parameters were found varying as a power of lateral pile/soil stiffness, on the basis of which hyperbolic P–Y curves in sand were proposed. The predictive capabilities of the proposed P–Y curves were assessed by predicting the soil/pile response in full-scale tests as well as in centrifuge tests and a very good agreement was found between the computed deflections and bending moments, and the measured ones. Small-sized database of full-scale pile loading tests in sand was built and a comparative study of some commonly used P–Y curve methods was undertaken. Moreover, it was shown that the load-deflection curves of these test piles may be normalised in a practical form for an approximate evaluation of pile deflection in a preliminary stage of pile design. At last, a parametric study undertaken on the basis of the proposed P–Y curves showed the significant influence of the lateral pile/soil stiffness on the non-linear load-deflection response.

Sıvılaşma, Sıvılaşma Nedir? Sıvılaşma Analizi, Zemin Sıvılaşması Nedir? Zeminlerin Sıvılaşabilirliği, Zemin Sıvılaşması İle İlgili Genel Tanımlar, Zemin Sıvılaşması İçin Mühendislik Analizleri ve Değerlendirmeler, Zemin Sıvılaşmasının Analiz Aşamaları, Zemin Sıvılaşması İçin Gerekli Koşullar Nelerdir? Zemin ve Temel Etüdü Uygulama Esaslarında ve Rapor Formatında Sıvılaşma Konusunun Geçtiği Bölümler, Hangi Tür Zeminler Sıvılaşmaya Daha Yatkındır? Zemin Sıvılaşmasının Mühendislik Değerlendirmesi, Ön Sıvılaşma, Gerçek Sıvılaşma, Sınırlı Ön Sıvılaşma-Çevrimsel Hareketlilik, Kum Kayması, Mikroskobik ve Makroskobik Sıvılaşma, Zemin Sıvılaşmasının Çeşitleri Nelerdir? Zemin Sıvılaşması Nasıl Oluşur? Zemin Sıvılaşmasına Etki Eden Faktörler Nelerdir? Zemin Özelliklerinin Sıvılaşmaya Etkisi, Zemin Sıvılaşmasına Hangi Tür Zeminlerde Rastlanılır? Zemin Sıvılaşması İçin Temel Analizler, Zemin Sıvılaşması İçin Arazi Araştırmaları ve Deneyleri, Zemin Sıvılaşmasının Etkileri ve Sonuçları Nelerdir? Zemin Sıvılaşması Nasıl Gözlenir?Zemin Sıvılaşması-Deprem İlişkisi Nasıl Açıklanabilir? Zemin Sıvılaşması İle İlgili Genel Bilgiler, Zemin Sıvılaşması İle İlgili Alınması Gereken Tedbirler, Önlemler ve Tavsiyeler, Zemin ve Temel Etüdü Uygulama Esaslarında ve Rapor Formatında Sıvılaşma İle İlgili Bilgiler, Ankara, Jeoloji, Jeoloji Mühendisliği, Jeoloji Yüksek Mühendisi, Türkay Ercan Şengöz. (Türkay Ercan Şengöz tarafından yayımlanan her çeşit harita, bilgi ve belgelerin her hakkı saklıdır. Her ne şekilde ve amaçla olursa olsun bu bilgi ve belgelerin kaynak belirtilmeden kullanılması, yazılı izin alınmadan elektronik, optik, mekanik veya diğer yollarla dağıtılması, çoğaltılması, basılması, değiştirilmesi, paylaşılması, kopyalanması ve internet sitelerinde kullanılması durumunda gerekli hukuki yollara başvurulacak ve yasal işlem başlatılacaktır. Önemle duyurulur. Bu platformda veya diğer platformlarda paylaşmış olduğum tez veya akademik kapsamdaki çalışmalarımın içerisindeki bütün bilgilerin etik davranış ve akademik kurallar çerçevesinde elde edilerek sunulduğunu, akademik çalışmalarımın tez yazım kurallarına uygun olarak hazırlandığını hatırlatıyor, bana ait olan her türlü ifade ve bilginin kaynağına eksiksiz atıf yapılması gerektiğini bildiriyor, sevgi ve saygılarımı sunuyorum.)

In the present paper, a method of analysis for calculating the pressure intensity corresponding to a given settlement for a rectangular footing resting on reinforced soil foundation has been presented. The process has been simplified by presenting non-dimensional charts for the various terms used in the analysis, which can be directly used by practicing engineers. An empirical method has been suggested to find out the ultimate bearing capacity of footing on reinforced soil. The results have been validated with large-scale model tests also. The procedure has been made clear by giving an illustrative example.

Five series of test blocks of Pendeli marble with artificially created discontinuities of different crack densities (simulating three mutually orthogonal joint sets) were tested in uniaxial compression in order to study the effect of discontinuities on: (a) the compressive strength and the modulus of elasticity, and (b) certain fracture energy parameters expressed by the ratio W A/W V, where W A is the surface energy and W V the volume elastic strain energy. Mathematical relationships are derived similar to those suggested by other authors relating strength parameters to crack densities. Such relationships clearly show a reduction in strength with increased crack density. The experimental results obtained permit the extension of Persson's relation (which refers to ideal intact rock) to the more realistic case of discontinuous rock mass by introducing the appropriate term that takes into consideration the effect of rock mass discontinuities on the energy ratio W A/W V. A comparison between laboratory results and field observations was subsequently carried out assuming the rock mass to behave as a linearly elastic material, obeying the Hoek and Brown failure criterion. This comparison showed that laboratory results can be extended to larger scale. Furthermore, in order to predict the in situ strength and stability of a rock mass in uniaxial compression (which is of major importance in underground excavations) certain concepts are proposed based on laboratory tests, in situ investigations and first principles of linear elastic fracture mechanics.

Detailed geotechnical data is often a major unknown factor in open pit design and mining, the lack of which constitutes a significant risk in any mining venture. As geotechnical data is accumulated so the risk of unforeseen conditions reduces, and so safety and productivity can be increased. Previously, most geotechnical work undertaken at open pit mines has focused on the slopes. The work done at Sandsloot open pit situated on the northern limb of the Bushveld Complex, 250 km north east of Johannesburg, however, has involved using geotechnical data for production, as well as slope stability benefits. Solutions to production problems encountered in a rapidly developing open pit are best formulated once some geotechnical control at the pit has been attained. At Sandsloot open pit this was achieved by delineation of geotechnical design zones from a detailed face mapping and drilling programme. Optimum design parameters then were assigned to these zones and geotechnically related problems assessed. This allowed slope management programmes to be initiated, as well as slope optimization of the hangingwall. The latter resulted in an improved slope configuration and an increase in the ultimate angle of the wall by 7°. This resulted in substantial savings, as well as an improvement in safety. In addition, the zones can be used for planning, costing and pit scheduling. The methods have proved successful in optimizing blast fragmentation and thereby loading, crushing and milling rates; in reducing secondary blasting and improving floor conditions; and in reducing drilling, blasting and comminution costs.