|
|
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 … |
|
|
Spang [Spang87] has classified the subsoil according to its potential for steerability (Tabelle 4.3.5.7) and thus touches upon three different phenomena:
|
|
|
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 … |
|
|
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 … |
|
|
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] : |
|
|
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 … |
|
|
According to DIN 1054 [DIN1054:2005] and because of its different behaviour under load caused by structures, the subsoil is divided into natural soil (cohesive and noncohesive soils as well as organic soils), into rock and into piled ground. |
|
|
Hydrogeology is the science of the behaviour of water in the underground irrespective of whether the condition of the water is solid (ice), fluid (groundwater) or gaseous. Hydrogeology also includes the interchange between groundwater and surface water (receiving water and bank-filtrated water). In general, water moves in the underground within the cavities or voids of the soil, the fissures and joints of the rock and the cave systems of the karst … |
|
|
Sources of information that can be used for this purpose are:
|
|
|
(Image: Example of an aerial photograph (original scale approximately 1:5000) [FI-Spang] taken by [FI-Aerow]) Aerial and satellite photographs are methods of geological remote sensing (meaning recording and mapping of appearances from a distance without immediate contact to the object). Geophysical methods are also utilized in geological remote sensing [Reute92]. Various recording methods are used for remote sensing including radar, heat radiation (… |
|
|
Irreplaceable for a first estimation of the feasibility and for determination of a subsequent direct investigation program is the surface access and inspection of the planned project alignment and its nearby surroundings. By means of engineering geological overview-mapping of existing explorations, by means of observations of the morphological and hydro-geological conditions and also with a view to hillside movements and observing the vegetation, … |
|
|
Preliminary exploration measures are carried out at the beginning of planning. The acquisition and analysis of already existing documents and archive material as well as a site visit permit a first orientation of the existing subsoil conditions and assist in the selection of subsequent detailed measures in the main exploration phase. The following possibilities are available for preliminary exploration [Kraut98] :
|
|
|
Natural exploration is the opening up of the underground (e.g. by the effect of geodynamic processes) in which the rock or soil material or the geological strata sequence can be investigated. In mountainous regions for instance, natural explorations are hillsides at which rock material strata are visible and in flat lands, erosion channels can be inspected. In the same sense, exposed deposit (e.g. of sand, clay or gravel) must be assessed in the course … |
|
|
In large projects, e.g. when jacking pipes of large diameter in which the soil is excavated at greater depths, deep explorations in the form of exploration galleries and shafts can be useful. These hand mining explorations permit extensive engineering geological acquisitions and sampling. |
|
|
A trial pit (pit or trench to DIN 4124 [DIN4124:2002]) is an artificially created excavation for inspecting the subsoil, for sampling and for carrying out field tests [DIN4021]. It can be man accessible or non-man-accessible. Trial pits are suitable mainly for explorations above the groundwater level and for low investigation depths [DIN4021]. As a rule, trial pits are unsuitable for inner urban regions due to the artificial surfacing and the intensive … |
|
|
(Image: Example of a borehole legend for boring in soil by continious extraction of cores to DIN 4022 Part 3 [FI-Spang]) Boring or drilling permits exploration in soil and rock up to great depths. Its execution is also not much hindered by groundwater [DIN4021]. Depending on the type of soil, various methods are used (rotary, dry core, dynamic core or pressure core drilling) in order to remove the soil. The DIN 4021 provides an overview of the application … |
|
|
(Image: Exploration and investigation methods within the scope of geotechnical investigations) "Direct exploration is exploratory work done at natural or man-made exploration points which permits the ground (remark: subsoil) to be visually examined, soil and rocks to be sampled and field testing to be carried out" [DIN4020:2003] [DIN4020:2003]. In the direct exploration method, information can be gathered on strata or bedding joints, types of rock … |
|
|
(Table: Types and Application areas of probing apparatuses to DIN 4094 [DIN4094-1] [DIN4094-2a] [DIN4094-4] [DIN4094-5]) According to DIN 4094 [DIN4094-1:2002] [DIN4094-2:2002] [DIN4094-4:2002] [DIN4094-5], the term probing, also called sounding or penetration test, is defined as, an indirect subsoil exploration method in soils by means of usually vertical penetration of a probe with measurement of characteristic values of penetration resistance. One … |
|
|
(Image: Example of the execution of reflexion seismic for groundwater search [FI-DMTb]) In reflexion seismic (Bild 4.5.2.2.2.1.1), the waves created at the surface and reflected from contrasting surfaces below ground are received at short distances from the source (relative to the target depth). The data received from the multi-channel telemetric apparatus, usually very comprehensive, can be processed and presented by special computer methods in such … |
|
|
(Image: Example of the execution of refraction seismic for contaminated soil exploration [FI-DMTb]) With refraction seismic (Bild 4.5.2.2.2.1.2), the waves are received at a greater distance from the source (relative to target depth). This means that, besides the reflexion from the subsoil, waves are also recorded that have used the fastest route between source and receiver and thus show the first returns of the seismic signals. Computer programs have … |
|
|
Seismic tomography [Herbs98] [Spang91] provides an area figure of the distribution of the compression wave velocity and the amplitude damping and therefore an indirect depiction of the distribution of certain material properties. It relies on the observation of mechanical vibrations that occur artificially or naturally during earthquakes. A condition of their application is the creation of boreholes in the region which is to be examined. Information … |
|
|
In acoustic seismic (Bild 4.5.2.2.2.1.4), the soil particles are vibrated by means of acoustic signals (airborne sound), which change in their frequency with time (sweep), in contrast to using impacts, explosives, etc. where a single impulse creates the seismic waves. The advantage of the acoustic source when compared to the other seismic sources is in its handiness, freedom from destruction and its better reproducibility and regularity of the seismic … |
|
|
Seismic is by far the most important and widespread method of geophysical exploration used for searching for deposits (oil, gas, coal) and also provides important structural information for the engineering and environmental fields. In the seismic method, elastic waves and wave fields are used as the information carriers and these can be processed to provide figures of the underground. This permits a direct view of its complex structure. The subsoil … |
|
|
(Image: Physical measurement principle of magnetism [Lenz97]) The earth's magnetic field is very strongly influenced on the surface by the upper layers or strata of the underground. In the region in which engineering geophysics occurs, these are not the layers themselves but the structures contained in them such as iron components, bunkers, tanks, beams, pipelines, waste, barrels and reinforced concrete foundations. Often, these iron components are … |
|
|
In the process of Electromagnetic Induction (EMI), the subsoil is subjected to an alternating field by means of a coil and this induces a secondary field. This, again, superimposes itself on the exciting field. The resulting field is measured by a receiver coil. The frequency range used in the EMI method ranges from 10 Hz to 2 MHz. The coil spacings vary from a few metres to about 100 m. Electromagnetic methods react very sensitively to zones of enhanced … |
11088 search results:
