The resulting velocity gradient style of interpretation presents very different representations of the subsurface compared to traditional interpretations. This paper presents two examples of preparation of seismic sections as a basis for geotechnical design of foundations. In this paper, the anthropogenic effects on the Badas peat dome were studied for three survey areas using seismic refraction surveys, core analysis and single well tests. Therefore is of major interest to have an improved knowledge upon the hazardous geological features, to evaluate them and to, Possibilities of protection of a construction excavation during the construction of deep foundations for a bridge in riverbed are tested in this work. Introduction and General considerations Seismic reflection is the most widely used geophysical technique. All rights reserved. Reflection seismology (or seismic reflection) is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves.The method requires a controlled seismic source of energy, such as dynamite or Tovex blast, a specialized air gun or a seismic vibrator, commonly known by the trademark name Vibroseis. In most cases a 12-channel system was used. One of the basic conditions that mentioned calculations have to satisfy is the compatibility of structure dislocation and soil. In principle this means that the refraction arrival of interest is approximately horizontal in the travel-time diagram. Integrated interpretation of geotechnical and geophysical datasets allowed to have an improved knowledge upon the hydrogeological setting in this medium/low-very low permeability sediments, to locate areas affected by historical landslides but also zones with active terrain movement. GR allowM fosr som e variatio inn th e surface topograph as wely al s lateral variation in the seismic velocit oyf the upper layers Th. Refraction tomography, another method of interpreting seismic refraction data, is capable of modeling these complex velocity structures. The velocity structure of a landslide mass, the depth to the failure surface, and the lateral extent of a landslide are variables that may be estimated using seismic refraction. 2. Consolidation grouting has been carried out under reactor buildings upto 15m depth and surrounding area upto 10m depth. Seismic refraction and reflection profiles across the northern Cordillera show the crust to be nearly 50 km thick under the south-eastern Canadian Cordillera and parts of northern Alaska (Figure 2).Below the Intermontane Plateau System in Alaska and northern Canada, it is about 35 km thick, and under the southern Canadian Cordillera only 30 km thick. MODELING OF A PROTECTIVE STRUCTURE FOR THE CONSTRUCTION OF DEEP FOUNDATIONS IN RIVERBED, Comparison of standards for conducting CIU tests and analysis of test results, Seismic refraction in relation to geotechnical information for (road) construction contracts, IMPROVEMENT OF ROCK STRATA FOR FOUNDATION OF REACTOR BUILDINGS. The apparent vertical displacements in the bedrock refractor may indicate the landslide is a deep-seated feature incorporating bedrock as well as surficial deposits. Looks like you’ve clipped this slide to already. methoe d use a principls e of Our new CrystalGraphics Chart and Diagram Slides for PowerPoint is a collection of over 1000 impressively designed data-driven chart and editable diagram s guaranteed to impress any audience. Abstract . 2/GPH221L9 KSU 2012-2013 I. Seismic Refraction Method Overview (2) Prepared by Dr. Amin Khalil 2. Standards currently in use are compared, and their applicability in real-life design situations is analyzed. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Clipping is a handy way to collect important slides you want to go back to later. In one example, the GRM was effective in modeling a landslide with abrupt changes in the depth to the top of the lowermost velocity unit, interpreted to be bedrock. Geological Society London Engineering Geology Special Publications. In addition to the routine laboratory tests on rock core samples, a number of field tests such as gamma logging, seismic cross-hole tests, Percolation test and cyclic plate load tests were carried out to assess the influence of calcareous material on the overall quality of the foundation rock stratum. Arrivals on a seismic reflection record can be seen in figure 4. Using first arrival picks, refraction tomography develops a best-fit velocity model by iteratively comparing different velocity distributions with observed data. In particular, a sand horizon underlying the peat deposits was identified which has the potential to be a significant hydrogeological flow unit. An interface depth must be interpreted from change in the velocity gradient rather than as a distinct boundary utilizing Snell's Law. This in turn can lead to costly errors in tendering and in construction planning and often to protracted contractual claims. As the angle of incidence is increased, the geometry results in a head wave travelling horizontally in layer 2. other seismic refraction interpretation method as the Time-Interceps such or Crossovert - Distance methods. Before stacking reflection seismic data, a normal move-out correction is applied. Velocity does not necessarily increase with each successively deeper layer. The site is located on the East coast of India in Gulf of Mannar. This can be achieved by doing the … The receivers are arranged to one side of a shot, which is 15 m from the first geophone. Since v1 > v2 the wave is refracted towards the horizontal. SAŽETAK Provođenje troosnih pokusa i upotreba rezultata ispitivanja nedvojbeno znatno doprinose racionalizaciji tijekom izgradnje geotehničkih i općenito građevinskih konstrukcija. Također je dan i osvrt na zadavanje pokusa uz specifičnosti materijala koji spada u raspon tvrdih tla odnosno mekih stijena. Based on the previous analyses, two new methods for calculation of shallow foundations settlements are developing, which both take into account the real soil behaviour at very small strains. G.Mitrovic, Application of seismic refraction studies in the design of viaducts; First In refraction seismology as well as in global seismology we often find travel-time diagrams where reduced time is used. Use of this approach has been critical in achieving substantial reductions is cost overruns attributable to geotechnical conditions. 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