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Nov 04, 2004 |
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Inspection, in accordance with ATV-M 143E Part 1 [ATVM143-1:1989] is understood to be: Measures for Determining and Evaluating the Actual Condition Inspection plays a central role in rehabilitation and maintenance. Its task is the preparation of data and information on the actual condition and the current wear reserve of the respective unit under review or on points of damage to it, and to recognise their causes at an early stage in order that rehabilitation … |
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The inspection of structures is carried out either as planned measures, i.e. regularly or at regularly timed intervals (Inspection strategy) or only when, in the course of operation, obvious changes can be seen (Failure strategy). In addition, inspections are carried out in order to investigate possibilities for changes of utilisation of a structure. Contrary to the practice up to the present, which preferred the failure strategy, the inspection strategy … |
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Feb 16, 2011 (Image: Manhole top raised above street level as a result of settling) The aboveground walk-through and examination of the street and ground surface of the sewer section in the catchment area represents the simplest form of inspection. In this way, possible effects of damage in the sewers, e.g. in the region of the manholes (Abschnitt 1.8) and the street surface can be recognised and taken into consideration in the planning and execution of internal … |
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Nov 19, 2004 The seismic method is by far the most important and widely used method of exploratory geophysics with which deposits (oil, gas, and coal) are explored and this method also provides the engineering and environmental fields with important structural information. In the seismic method, the information is carried by elastic waves and wave fields, which can be processed to provide figures of the underground. This enables a direct view of its complex structure … |
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Nov 19, 2004 In the seismic reflection method, the reflected waves that were created at the surface and reflected by the border surfaces are registered (relative to the target depth) within short distances from the source. The very comprehensive data material from the multi-channel telemetric apparatus can be processed and depicted with the aid of special computer methods in such a way that an underground structure is shown that can be directly interpreted. In … |
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Nov 19, 2004 In the seismic refraction method, the waves are registered at greater distances from the source (relative to the target depth). This means that, besides the reflexions from the underground, waves are also received that have used the quickest path between source and receivers and thus provide the first application in the seismic signals. Computer programs have been developed very recently to process these wave fields in such a way show that direct … |
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Nov 19, 2004
Seismic tomography provides a laminar figure of the distribution of the compression wave velocity and the amplitude damping and thus indirectly a depiction of the distribution of certain material characteristics. A pre-condition of their application … |
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Feb 16, 2011 In air gun seismics (Bild 4.3.1.2.5) (Bild 4.3.1.2.5), the soil particles are excited by means of acoustic wave signals that vary in their frequency with time (sweep) to oscillations. This is in contrast to hammering, explosives, etc. where a single impulse generates the seismic waves.
The advantage … |
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Nov 19, 2004 (Image: Physical measurement principle of magnetism [Lenz97]) The magnetic field of earth is very strongly influenced at the surface of the ground by the topmost layer of the underground. In the application region of engineering geophysics, these are not the layers themselves but the structures they contain, such as, for example iron substances, bunkers, tanks, beams, pipelines, scrap, containers and reinforced concrete foundations. Often, these iron … |
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Feb 16, 2011 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. Bild 4.3.1.2.7 shows the manual measuring. The frequency region used by the EMI method ranges from about 10 Hz to 2 MHz, the coil spacing varies from a few metres (Bild 4.3.1.2.7) to approximately … |
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Feb 16, 2011 In the geo-electrical method, a weak direct current is fed into the underground by means of electrodes. Sensors capture the resulting stationary field potential, which is influenced by the distribution of conductivity of the underground. By means of suitable model calculations, it is possible from these measurement values to obtain the distribution of the true specific resistance in the underground below the sensor point, along a profile or in a … |
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Nov 19, 2004 In the soil or geo-radar (EMR = Electro-Magnetic Reflection), an impulse-type high frequency radio wave is sent into the soil from an antenna. The signal is partly reflected from border planes and interference bodies, and sensed by a receiver. The radargram built up in this way can be interpreted to show the underground structures [Lenz97]. Bild 4.3.1.2.9 shows the amplitudes of the reflected signal that change with time as a single point depiction. … |
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Feb 16, 2011 Very important for the information received and the reliability of geophysical measurements are the method of the measuring and the proper arrangement of the measuring instruments. It is in the nature of the geophysical data to provide results that can mean a number of things and there is a high degree of complexity in the alternating effects between exciter signals and the answering behaviour of the measured object. Thus, there is a requirement, … |
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Nov 19, 2004 Geophysical Soil Exploration |
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Nov 19, 2004 Rehabilitation and Maintenance of Drains and Sewers Building Site and Subsoil Exploration by Means of Excavation "Scraping is an artificially created opening for obtaining a view of the construction site, for taking samples and for carrying out field tests." It can be carried out by accessible or non-man-accessible means. Scrapings are suitable mainly for tests above the groundwater or for small inspection depths [DIN4021]. |
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Nov 19, 2004 Rehabilitation and Maintenance of Drains and Sewers Building Site and Subsoil Exploration by Means of Excavation "Boring makes possible the exploration in soil and rock up to great depths, its execution is not hindered substantially by groundwater" [DIN4021]. Various methods are used in order to remove the soil depending on the type (rotation, dry core, ram core or compression core drilling). Excavation boring can also be used for observing the groundwater to establish the position, quality and quantity in waterlogged layers or as groundwater measuring positions (… |
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Feb 16, 2011 Rehabilitation and Maintenance of Drains and Sewers Building Site and Subsoil Exploration by Means of Excavation According to [DIN4094], the term sounding is defined as "an indirect construction site excavation process in soils, usually by the introduction of a sensor for measuring characteristics of the ingress resistance." One distinguishes between ram, pressure and rotating wing sounding. The various types and possibilities of application of the probe instruments are depicted in Tabelle 4.3.1.3.3. (Table: Types and application possibilities of the sounding … |
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Nov 19, 2004 Building Site and Soil Exploration by Means of Excavation |
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Nov 19, 2004 External inspection comprises all measures that are carried out from the surface. These include:
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Feb 16, 2011 (Image: Sewer inspection system for accessible sewage installations [FI-Gully]) The direct optical inspection is carried out by viewing whilst traversing or driving. For structures of drain and sewer systems such as manholes or backflow structures, because of their dimensions or their geometry, it presents in most cases the only sensible or possible measure for determining the actual condition. In the sections of the sewer, this method is permitted … |
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Feb 16, 2011 Sewer TV cameras, also called Remote Sewer Eyes, are exclusively used today for optical inspection of non-man-accessible sewers. The installations are constructed on the module principle and can be adapted to almost all requirements by the exchange of lenses, camera and lighting units and the selection of various guide sleds or slides or motorised units, pull or push arrangements and by means of the utilisation of corresponding operating and display … |
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Feb 16, 2011 As regards the conveying and control installations, one distinguishes between non-self-propelling and self- propelling cameras. In small nominal sizes, short sections of the sewer and laterals, the camera is usually pushed directly through the sewer by means of endless or extendable glass fibre rods whereby, under certain conditions, even 90° bends present no problems. For controlling or centring the camera unit, radially arranged brushes, sleds … |
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Nov 19, 2004
The observation and control installations required for a sewer inspection are either built into an instrument case or are fixedly installed in special inspection vehicles. The instrument case that is usually used for private domain sewers, laterals and for sections of the sewer not accessible to motorised vehicles is equipped, … |
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