Wyniki wyszukiwania - Biblioteka Nauki

1

The Possibility of Setting Dynamic Shear Modulus Based on Multi-Channel Analysis of Surface Waves

100%

Matula R. , Czaja K. , Ślusarczyk R.

|

tom nr 4

4658--4664, CD6

EN

Considering logistic as a process of planning, implementing and controlling the efficient and cost-effective flow of raw materials, finished products and relevant information from point of origin to point of consumption it must be stated that effective transport is an indispensable factor that determines the process flow of goods, services, etc. Consequently, transport depends on fact how effectively net of highway is constructed, providing the best possible solution to the movement of goods and services. Design of roads and highways that are without doubt the basics of logistics activities depends on many factors, which at first glance do not have much to do with logistics in the proper sense of this word. Post designate the route of the road or highway seems to be a strategic issue both from a technical point of view as well as its subsequent exploitation. Construction of the road network in the simplest, possible way consist of building roads along as straight lines as possible. But it may be difficult to implement be-cause of many reasons. Variable environmental conditions are one of the causes that contribute to changes in the originally assumed location of the investment, which entails significant costs. Non-invasive seismic survey can be an answer for series of questions related to the stability of the ground, before the start of the investment. Results of seismic measurements can be converted to the dynamic mod-ulus of elasticity. The article presents description of possibilities of evaluation shear modulus in Holocene sediments from seismic measurements.

PL

Biorąc pod uwagę logistykę jako proces planowania, wdrażania i kontrolowania sprawnego oraz efek-tywnego przepływu surowców, wyrobów gotowych oraz odpowiedniej informacji z punktu pochodzenia do punktu konsumpcji, należy stwierdzić, że sprawny transport jest niezbędnym czynnikiem, który decyduje o płynności przepływu towarów, usług, itp. Zależy on od konstrukcji sieci dróg i autostrad, które powinny zapewniać najlepsze z możliwych rozwiązanie dla przepływu towarów i usług. Projektowanie dróg i autostrad, na których opiera się szereg działań logistycznych, zależy od wielu czynników, które na pierwszy rzut oka nie mają wiele wspólnego logistyką w ścisłym znaczeniu tego słowa. Proces wyzna-czenia trasy drogi lub autostrady wydaje się być strategicznym problemem zarówno z punktu widzenia technicznego, jak i jej późniejszego wykorzystywania. Budowa sieci dróg w najprostszy z możliwych sposobów, tzn. w postaci zbliżonej do linii prostej, może być trudne w realizacji z wielu powodów. Jedną z przyczyn są zmienne warunki naturalne, które przyczyniają się do zmian w pierwotnie założonej lokalizacji inwestycji, co pociąga za sobą znaczne koszty. Odpowiedzą na szereg pytań związanych ze stabilnością podłoża przed rozpoczęciem właściwej inwestycji mogą być badanie sejsmiczne. Wyniki tych badań mogą być przeliczone na wartości dynamicznych modułów sprężystości.

2

Subsurface velocity model in post-glacial deposits based on multichannel analysis of surface waves

71%

Matula R. , Lewińska P.

|

tom Vol. 38, no. 4

505

EN

First introduced and developed in the 1990s, the multichannel analysis of surface waves (MASW) is one of the active, seismic methods created for shallow seismic imaging. Surface waves generated from a sledge hammer were used for delineation of subsurface structures. MASW is analyzing the propagation velocities for each component of surface waves by generating the dispersion curves, and then as a result produces shear-wave velocity (Vs) profiles below the surveyed surface. A Vs distribution in the depth domain is obtained in 1-D or 2-D variant after a quite simple inversion procedure. Shear-wave velocity iVs) is one of the elastic constants, closely related to changes in geology. Weathering zone in post-glacial area, as one of the most complex geological forms, were chosen to check MASW ability to evaluation near-surface, folded structures. Data were acquired for typical MASW continuous profiling schema in 2 meters intervals and performed using land-streamer at the distance of about 200 m, along previously existed reflection seismic line. The analysis was supported by records from previously made reflection seismic investigations. Image of glacial till on MASW 2-D map is characterized by appearance of mix clay-sandy layers, folded and locally discontinued. Furthermore, the most of detected middle layers from 0 m up to 30 m deep form pile of thrust slices. Application of obtained subsurface model could be considered at a two main stages. First of them has a geological background where continuous Vs distribution supporting geological and geomorphological works. The second one is connecting with prospecting seismic where 2-D Vs map could be used for static purposes.

3

Seismic characterization of an abandoned mine site

71%

Arosio D. , Longoni L. , Papini M. , Zanzi L.

|

tom Vol. 61, no. 3

611--623

EN

The near-surface rock structure that covers an abandoned marl mine nearby the village of Montevecchia (Italy) was investigated through a combination of seismic surveys. The methods selected for these investigations were refraction seismics and multichannel analysis of surface waves (MASW). A sort of transillumination experiment was also attempted. All the methods were successful and gave complementary information. Refraction seismics was used to characterize the upper low velocity layer and the second layer of the near-surface structure. The MASW method was necessary to assess the existence of a velocity inversion revealing the presence of a low velocity layer between the 2nd layer and a 4th high velocity layer covering the upper mine gallery. The transillumination experiment validated the presence of the 4th layer and gave an estimate of the average velocity that represents a lower boundary for the P-wave velocity within this layer. Both the refraction and transillumination data were analysed to derive average estimates of attenuation level and rock quality factor.

4

3D subsoil reconstruction of a mud volcano in central Sicily by means of geophysical surveys

51%

Grassi S. , De Guidi G. , Patti G. , Brighenti F. , Carnemolla F. , Imposa S.

|

tom Vol. 70, no 3

1083--1102

EN

The upwelling of fluids, subject to overpressure, along with discontinuities in the subsoil, causes the formation of geological structures known as mud volcanoes. These structures, very widespread in the world and in some cases located near inhabited centers, can represent a considerable risk factor for the population, as they can give rise to paroxysmal eruptions, even very violent. The assessment of the characteristics and structure of the subsoil of the areas affected by this phenomenon can prove to be a useful tool for risk mitigation. Non-invasive geophysical surveys were carried out in the area of the active cone of the Santa Barbara mud volcano in order to obtain a 3D characterization of the subsoil. Through the processing and integration of data derived from active and passive seismic surveys was obtained, a 3D model showing the seismostratigraphic subsoil structure. The electrical resistivity tomography surveys provided results comparable to those obtained from seismic surveys and supplied information on the perimetral areas of the mud volcano. The information obtained is useful to study the boundary conditions that influence short-scale activity. Furthermore, this study seeks to evaluate the possibility of using the proposed methodological approach for monitoring the variations that occur over time in the areas affected by mud volcanoes phenomenon.