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Also, according to ISO14688-1 [DINENISO14688:2004], volcanic soils are understood to be, "pyroplastic materials produced and formed by explosive volcanic eruption; e.g. pumice, scoria, volcanic ash." The particles of volcanic soils are generally blistered and the compactness or density of the strata (Abschnitt 4.3.1.4) is relatively low. The soils possess a characteristic colour that depends on the original magma or rock. The main components of … |
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With fine soils, the shape of the particle is solely dependent on the type of the mineral. Quartz, lime and dolomite are generally cubic, clay minerals generally flat and halloysite is longitudinal (elongated). With coarse soils, the particle shape and the roughness is dependent on the type of rock material as well as the transport and weathering history. Increasing transport distances leads to rounding of the edges and the smoothing of the particle. … |
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(Image: Flow chart for the identification and description of soils based on ISO 14688-1 [DINENISO14688a]) The primary differentiating feature of mineral soils is the size of the individual particles. This determination is the first step in the identification and classification of a soil type (Bild 4.3.1.3). A review of the identification of the type of soil with reference to particle size is shown in Tabelle 4.3.1.3. (Table: Identification and particle … |
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Density is used to describe the compactness by which the individual soil particles have arranged or chained. From this, direct assumptions can be made concerning the soil strength, the additional compaction or displacement capability or the water … |
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Cohesive soils change their state or condition with water content. With a very high water content, cohesive soils are liquid and, with reduction of water content, change from a liquid to a plastic state, then to a stiff and finally into a very stiff (hard) condition, which means that the soil is less deformable and its strength increases. The transitions from one condition to the other have been defined by Atterberg [Atter11] and are called consistency … |
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The determination of the uniaxial compressive strength qu of soils, also known as cylinder compressive strength is carried out according to DIN 18136 [DIN18136:2003] on cylindrical or prismatic test bodies at constant compression velocity and with unhindered side expansion. The uniaxial compressive strength is also used in the description of the condition of cohesive soils (Abschnitt 4.3.1.5) [Kezdi68] [Lambe69]. A proposal in this respect for clays … |
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(Image: Soil element under shear loading [Schmi96]) Soil is a structure made up of a framework of solid particles with water and air-filled pores and is therefore sensitive to shear loads that are caused by shear stresses (Bild 4.3.1.7). The fact that a borehole, an excavated cavity in the subsoil, or the working face is stable without supports is a result of the shear strength τ of the subsoil. For instance, this shear strength is lowest for dry sand … |
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Nov 28, 2006 Trenchless Technology for Installation of Cables and Pipelines Mechanical fundamentals of soil and rock (geotechnical parameters) (Image: Flow chart for the identification and description of soils based on ISO 14688-1 [DINENISO14688a]) Soil is a mixture of minerals and/or organic components without mineral cohesion. Separation of the mineral components according to particle size by means of simple sieving or sedimentation process is possible. A further characteristic is the importance of point contacts among the mineral particles. Basically, soils consist of several phases:
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A large zone of rock (rock mass) is not a monolithic body but is more or less divided by discontinuities [DS853]. Their spatial arrangement in the rock mass is called the geologic structure (Tabelle 4.3.2.1) [DINENISO14689:2004]. (Table: Examples of terms which may be used in the description of rock mass structure to ISO14689 [DINENISO14689a])
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As the measured compressive strength of a body can vary depending on the standards of the testing, the determination of the uniaxial compressive strength (UCS) of rock material should be carried out in Germany on the basis of an uniaxial compression test in accordance with DIN 18316 [DIN18136:2003] and the recommendations No. 1 of the Deutsche Gesellschaft für Erd- und Grundbau (DGEG), now called the Deutsche Gesellschaft für Geotechnik (DGGT) [… |
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Nov 28, 2006 Trenchless Technology for Installation of Cables and Pipelines Mechanical fundamentals of soil and rock (geotechnical parameters) ISO 14689 [DINENISO14689:2004] defines rock as, "a naturally occurring assemblage of minerals, consolidated, cemented or otherwise bonded together, so as to form material of generally greater strength or rigidity than soils". Rock material, according to ISO 14689 [DINENISO14689:2004] is, "the intact rock within the framework of the discontinuities." There are intermediate stages between solid and loose sediments. When testing solid rock and rock bond … |
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Nov 28, 2006 Trenchless Technology for Installation of Cables and Pipelines Mechanical fundamentals of soil and rock (geotechnical parameters) According to DIN 1054 [DIN1054:2005] a soil is termed, "made when it has originated due to filling or hydraulic filling". This is divided into:
Embankments, railway banks, waste dumps (landfills) as well as most of the surface regions under … |
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Nov 28, 2006 Trenchless Technology for Installation of Cables and Pipelines Mechanical fundamentals of soil and rock (geotechnical parameters) The following different soil characteristic and calculation values are of great importance for trenchless installation, for instance, in the determination of the required jacking forces, in structural calculations of jacking pipes and shafts, in the determination of soil deformation as well as in the estimation of the stability of the working face (Abschnitt 14) (Abschnitt 15.1). When no soil characteristics from field and laboratory tests are available, … |
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The DIN 18196 [DIN18196:1988] [DIN18196:2004] arranges the types of soil into soil groups only according to the material composition and independent of the water content and density of the soil. The following serve as classification characteristics [DIN18196:1988] [DIN18196:2004] :
For classification purposes, a soil sample must be allocated according … |
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In DIN 18300 "Contract procedures for building works - Part C: General technical specifications for building works; Earthworks" (ATV) [DIN18300-Cd], the subsoil is divided into seven soil and rock classes. The classification characteristic here is exclusively from the point of view of the ease of breakout (Tabelle 4.3.5.2). (Table: Soil and rock classes to DIN 18300 [DIN18300-Cd]) This soil and rock classification is not applicable for boring, drilling … |
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The soil and rock classes, for trenchless technology for installation of prefabricated pipes of any profile by means of pressing-in, pushing-in, ramming-in or pulling-in, [DIN18319:2000] (Bild 4.3.5.3) (Abschnitt 3.1) is defined in the Federal Republic … |
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The Unified Soil Classification System (USCS) of the ASTM (American Society for Testing Materials) Standard D2487-00 "Standard Classification of Soil for Engineering Purposes" [ASTMD248700] of the USA, divides soil into 15 classes (Tabelle 4.3.5.4) which are always described by a group symbol that comprises two characteristic letters [Weiß96b]. (Table: Soil classification according to the USCS (USA) [ASTMD248700]) Five letter symbols represent the … |
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(Image: Procedure for maesurement and calculation of RQD-value [Hoek95]) The Rock Quality Index (abbreviated to RQD-value or RQD-index) was developed in 1967 by Deere [Deere67] as a characteristic for describing rock and relies on the length of the intact segments of the bore core to designate the quality of the rock mass. The RQD-value provides the relationship L10/L in percent where L10 is the cumulative length of core pieces with intact length of … |
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The displacement capability of a soil is very important in trenchless installation especially in the soil displacement technique (Abschnitt 5.1) (Abschnitt 6). Besides the question of whether such a method is generally suitable for a particular application case, there are also certain influences of the soil displacement process on the immediate vicinity to be estimated (e.g. soil heave and subsidence at the ground surface (Abschnitt 15.1)) because … |
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Spang [Spang87] has classified the subsoil according to its potential for steerability (Tabelle 4.3.5.7) and thus touches upon three different phenomena:
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This classification proposal by Spang [Spang87] that can be used especially for pipe jacking with shield machines with partial excavation by hand (hand shields) or with mechanial partial excavation (Abschnitt 9.1), is based on a classification system for tunnel construction in soil described in [Proct77]. The quality of the types of soils described in the publication were converted into soil groups to DIN 18196 [DIN18196:1988] [DIN18196:2004] (Abschnitt … |
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The oldest classification proposal for measuring the effort when loosening and transporting the soil and rock during earthworks ("extraction difficulty") with a division into so-called extraction classes originated with Kögler in the year 1936 [Kögle36]. This classification sees soil and rock classes exclusively from a point of view of hand tools as extraction devices. The suitable removal tool for soil or rock is allocated here into eight extraction … |
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The abrasiveness of a rock material is understood in connection with trenchless installation as, a property when boring or drilling to cause a larger or smaller amount of wear of the excavation tool [Arnol93]. Although attempts are made to keep the wear as small as possible by means of technical parameters such as variation of the material quality, cooling and lubrication, tool wear cannot be avoided. The effects of this are, for instance [Arnol93] : |
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Nov 28, 2006 Trenchless Technology for Installation of Cables and Pipelines Mechanical fundamentals of soil and rock (geotechnical parameters) According to ISO 14688-2 [DINENISO14688:2004], soil classification is, "the assignment of soil groups on the basis of certain characteristics and criteria." The purpose of the classification is the establishment of unified evaluation properties which will make possible a preliminary estimation of the suitability of subsoil for certain civil engineering purposes and, by determining the properties and characteristics permit an approximate determination … |
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