Geological forward-prospecting using Tunnel-seismic-while-drilling (TSWD) method: A case study of the water supply project at Songhua River, China

Geophysics ◽  
2021 ◽  
pp. 1-57
Author(s):  
Shucai Li ◽  
Lei Chen ◽  
Bin Liu ◽  
Xinji Xu ◽  
Lanbo Liu ◽  
...  
Keyword(s):  
Water Supply ◽  
Seismic Waves ◽  
Economic Losses ◽  
Common Source ◽  
Songhua River ◽  
Pilot Signal ◽  
Safety Issues ◽  
Geological Conditions ◽  
Geological Information ◽  
Boring Machines

Unexpected geological heterogeneities in the tunnel lines often cause safety issues and economic losses during excavation using Tunnel Boring Machines (TBMs). Therefore, collecting geological information ahead of the excavation front is important to prevent geological disasters and ensure excavation safety. To predict the geological conditions ahead of the TBM-excavated tunnel in the water supply project at the Songhua River in China, the tunnel-seismic-while-drilling (TSWD) method was adjusted and then applied. First, common source gather (CSG) data were acquired to record TBM drilling noise (pilot signal and seismic waves); a processing approach (including normalization, cross-correlation, wave-field separation, and migration) was used to image the major relevant geological heterogeneities ahead of the excavation front. A synthetic study from a numerical model with a fault verified the feasibility of the modified TSWD method to identify and image geological interfaces. Then this method was applied to field data resulting from a TBM tunnel excavation project. The field test of the modified TSWD in the TBM tunnel revealed the fractured zones, fault boundaries, and a pre-excavated tunnel ahead, providing the required geological information for TBM tunneling and preventing geologically caused safety issues.

scholarly journals One-dimensional constrained inversion study of TEM and application in coal goafs’ detection

2020 ◽  
Vol 12 (1) ◽  
pp. 1533-1540
Author(s):  
Si Yuanlei ◽  
Li Maofei ◽  
Liu Yaoning ◽  
Guo Weihong
Keyword(s):  
Least Squares ◽  
Least Squares Method ◽  
Data Interpretation ◽  
Volume Effect ◽  
Underground Space ◽  
Attenuation Curve ◽  
One Dimensional ◽  
Transient Electromagnetic ◽  
Geological Conditions ◽  
Geological Information

AbstractTransient electromagnetic method (TEM) is often used in urban underground space exploration and field geological resource detection. Inversion is the most important step in data interpretation. Because of the volume effect of the TEM, the inversion results are usually multi-solvable. To reduce the multi-solvability of inversion, the constrained inversion of TEM has been studied using the least squares method. The inversion trials were performed using two three-layer theoretical geological models and one four-layer theoretical geological model. The results show that one-dimensional least squares constrained inversion is faster and more effective than unconstrained inversion. The induced electromotive force attenuation curves of the inversion model indicate that the same attenuation curve may be used for different geological conditions. Therefore, constrained inversion using known geological information can more accurately reflect the underground geological information.

scholarly journals Mapping, cluster detection and evaluation of risk factors of ovine toxoplasmosis in Southern Italy

2016 ◽  
Vol 11 (2) ◽  
Author(s):  
Roberto Condoleo ◽  
Vincenzo Musella ◽  
Maria Paola Maurelli ◽  
Antonio Bosco ◽  
Giuseppe Cringoli ◽  
...  
Keyword(s):  
Risk Factors ◽  
Geographical Information Systems ◽  
Southern Italy ◽  
Geographical Information ◽  
Economic Losses ◽  
Common Source ◽  
High Exposure ◽  
Campania Region ◽  
Source Of Infection ◽  
Serological Data

Toxoplasmosis, an important cause of reproductive failure in sheep, is responsible for significant economic losses to the ovine industry worldwide. Moreover, ovine meat contaminated by the parasite <em>Toxoplasma gondii</em> is considered as a common source of infection for humans. The aim of this study was to develop point and risk profiling maps of <em>T. gondii</em> seroprevalence in sheep bred in Campania Region (Southern Italy) and analyse risk factors associated at the flock-level. We used serological data from a previous survey of 117 sheep flocks, while environmental and farm management information were obtained from an analysis based on geographical information systems and a questionnaire purveyance, respectively. An univariate Poisson regression model revealed that the type of farm production (milk and meat vs only meat) was the only independent variable associated with <em>T. gondii</em> positivity (P&lt;0.02); the higher within-flock seroprevalence in milking herds suggests that milking practices might influence the spread of the infection on the farm. Neither environmental nor other management variables were significant. Since a majority of flocks were seasonally or permanently on pasture, the animals have a high exposure to infectious <em>T. gondii</em> oocysts, so the high within-flock seroprevalence might derive from this management factor. However, further studies are needed to better assess the actual epidemiological situation of toxoplasmosis in sheep and to clarify the factors that influence its presence and distribution.

scholarly journals Lithospheric structure models applied for locating the Romanian seismic events

1994 ◽  
Vol 37 (3) ◽  
Author(s):  
M. Rizescu ◽  
E. Popescu ◽  
V. Oancea ◽  
D. Enescu
Keyword(s):  
Constant Velocity ◽  
Seismic Waves ◽  
Seismic Events ◽  
Lithospheric Structure ◽  
Structural Units ◽  
Data Set ◽  
Velocity Models ◽  
Seismic Sequences ◽  
Geological Information ◽  
Propagation Velocities

The paper presents our attempts made for improving the locations obtained for local seismic events, using refined lithospheric structure models. The location program (based on Geiger method) supposes a known model. The program is run for some seismic sequences which occurred in different regions, on the Romanian territory, using for each of the sequences three velocity models: 1) 7 layers of constant velocity of seismic waves, as an average structure of the lithosphere for the whole territory; 2) site dependent structure (below each station), based on geophysical and geological information on the crust; 3) curves deseribing the dependence of propagation velocities with depth in the lithosphere, characterizing the 7 structural units delineated on the Romanian territory. The results obtained using the different velocity models are compared. Station corrections are computed for each data set. Finally, the locations determined for some quarry blasts are compared with the real ones.

scholarly journals Exploration of Geotechnical Engineering Investigation under Complex Topographical and Geological Conditions

2019 ◽  
Vol 2 (4) ◽  
pp. 20
Author(s):  
Yan Gao ◽  
Guihe Liang ◽  
Yanyong Zhou
Keyword(s):  
Water Supply ◽  
Inner Mongolia ◽  
Geotechnical Engineering ◽  
Tube Wells ◽  
Geological Conditions ◽  
Engineering Investigation ◽  
Supply Tube

This paper will explore the geotechnical engineering investigation technology under the complex topographical and geological conditions, and introduce how to construct the water supply tube wells faster and better under the complex topographical and geological conditions by taking Inner Mongolia as an example, so as to provide reference for the relevant professionals

Anchor Spacing Design of Pre-Stressed Tunnel Concrete Lining with Un-Bonded Annular Anchors for Songhua River Water Supply Project

2017 ◽  
Vol 737 ◽  
pp. 505-510 ◽  
Author(s):  
Jin Pi ◽  
Yu Fei Zhao ◽  
Rui Lang Cao ◽  
Zhi Xin Jia
Keyword(s):  
Water Supply ◽  
River Water ◽  
Design Method ◽  
Water Pressure ◽  
Poor Quality ◽  
Concrete Lining ◽  
Songhua River ◽  
Equivalent Load Method ◽  
Equivalent Load ◽  
The Cost

At present, annular anchor pre-stressed tunnel Concrete lining is the main design method of poor -quality surrounding rocks, thin covering and high internal water pressure tunnel. Based on the contact of tendons and concrete, the annular anchor lining can be classified into bonded and un-bonded. Cable spacing is one of the key parameters in the design of the un-bonded annular anchors pre-stressed concrete lining. The optimal anchor spacing can not only meet the demand of the project, but also save the cost of construction. In this paper, the anchor spacing is studied in the design of pre-stressed tunnel concrete lining with un-bonded annular anchors for Songhua River water supply project. The equivalent load method and solid modeling method are combined in Flac3d 3D modeling. Numerical simulation of pre-stressed effects for different anchor spacing in tension and operation of the concrete lining were analyzed. The optimal anchor cable spacing is received, which is a reference for the design and construction of similar projects in the future.

Scalar reverse‐time depth migration of prestack elastic seismic data

Geophysics ◽  
2001 ◽  
Vol 66 (5) ◽  
pp. 1519-1527 ◽  
Author(s):  
Robert Sun ◽  
George A. McMechan
Keyword(s):  
Seismic Waves ◽  
Velocity Model ◽  
P Wave ◽  
Common Source ◽  
Reverse Time ◽  
S Wave ◽  
Wave Source ◽  
Reflected Waves ◽  
S Waves ◽  
Elastic Data

Reflected P‐to‐P and P‐to‐S converted seismic waves in a two‐component elastic common‐source gather generated with a P‐wave source in a two‐dimensional model can be imaged by two independent scalar reverse‐time depth migrations. The inputs to migration are pure P‐ and S‐waves that are extracted by divergence and curl calculations during (shallow) extrapolation of the elastic data recorded at the earth’s surface. For both P‐to‐P and P‐to‐S converted reflected waves, the imaging time at each point is the P‐wave traveltime from the source to that point. The extracted P‐wave is reverse‐time extrapolated and imaged with a P‐velocity model, using a finite difference solution of the scalar wave equation. The extracted S‐wave is reverse‐time extrapolated and imaged similarly, but with an S‐velocity model. Converted S‐wave data requires a polarity correction prior to migration to ensure constructive interference between data from adjacent sources. Synthetic examples show that the algorithm gives satisfactory results for laterally inhomogeneous models.

scholarly journals Self-sustained vibrations in volcanic areas extracted by Independent Component Analysis: a review and new results

2011 ◽  
Vol 18 (6) ◽  
pp. 925-940 ◽  
Author(s):  
E. De Lauro ◽  
S. De Martino ◽  
M. Falanga ◽  
M. Palo
Keyword(s):  
Independent Component Analysis ◽  
Seismic Waves ◽  
Volcanic Tremor ◽  
Component Analysis ◽  
Independent Component ◽  
Common Source ◽  
Magma Flow ◽  
Volcanic Source ◽  
Non Linear ◽  
Low Dimensionality

Abstract. We investigate the physical processes associated with volcanic tremor and explosions. A volcano is a complex system where a fluid source interacts with the solid edifice so generating seismic waves in a regime of low turbulence. Although the complex behavior escapes a simple universal description, the phases of activity generate stable (self-sustained) oscillations that can be described as a non-linear dynamical system of low dimensionality. So, the system requires to be investigated with non-linear methods able to individuate, decompose, and extract the main characteristics of the phenomenon. Independent Component Analysis (ICA), an entropy-based technique is a good candidate for this purpose. Here, we review the results of ICA applied to seismic signals acquired in some volcanic areas. We emphasize analogies and differences among the self-oscillations individuated in three cases: Stromboli (Italy), Erebus (Antarctica) and Volcán de Colima (Mexico). The waveforms of the extracted independent components are specific for each volcano, whereas the similarity can be ascribed to a very general common source mechanism involving the interaction between gas/magma flow and solid structures (the volcanic edifice). Indeed, chocking phenomena or inhomogeneities in the volcanic cavity can play the same role in generating self-oscillations as the languid and the reed do in musical instruments. The understanding of these background oscillations is relevant not only for explaining the volcanic source process and to make a forecast into the future, but sheds light on the physics of complex systems developing low turbulence.

scholarly journals Coping with poor water supply in peri-urban Bandung, Indonesia: towards a framework for understanding risks and aversion behaviours

2017 ◽  
Vol 29 (1) ◽  
pp. 69-88 ◽  
Author(s):  
Anindrya Nastiti ◽  
Barti Setiani Muntalif ◽  
Dwina Roosmini ◽  
Arief Sudradjat ◽  
S V Meijerink ◽  
...  
Keyword(s):  
Water Supply ◽  
Risk Perceptions ◽  
Management Strategies ◽  
Water Source ◽  
Economic Losses ◽  
Socioeconomic Characteristics ◽  
Perceptions Of Risk ◽  
Shared Experiences ◽  
Actual Risk ◽  
Risk Management Strategies

This paper explores the daily risks of households with respect to dimensions of inadequate water access and supply (quality, quantity, continuity and affordability). We describe how perceptions of risk are shaped and how households seek to reduce possible health impacts and potential economic losses through aversion behaviours. To this end, households’ activities relating to water storage, treatment and usage, together with water source preference, were analysed using a qualitative approach. We developed a framework that describes actual risk, risk perceptions and aversion behaviours. Risk perceptions and the adoption of aversion behaviours of varying frequency and intensity are based on a complex interaction between personal and shared experiences that relate to water supply dimensions, socioeconomic characteristics, and social networking. Moreover, we discuss household risk management strategies and provide some recommendations aimed at improving future approaches to the study of aversion behaviours.

scholarly journals Sequence of studying engineering and geological conditions of mineral deposits from exploration to development

2020 ◽  
Vol 7 (7) ◽  
pp. 83-91
Author(s):  
Irina V. Abaturova ◽  
◽  
Ivan A. Savintsev ◽  
Liubov A. Storozhenko ◽  
Elvina D. Nugmanova ◽  
...  
Keyword(s):  
Large Scale ◽  
Geological Environment ◽  
Geological Time ◽  
Protective Measures ◽  
Early Stages ◽  
Geological Processes ◽  
The Earth ◽  
Geological Conditions ◽  
Geological Information ◽  
Further Development

geological environment. Actively change all the components of engineering-geological conditions (EGC), formed during the long geological time: the topography, structure of rocks, hydrogeological and permafrost conditions, are formed by geological processes and, at the same time on the surface of the Earth formed a new strata of man-made structures, and often man-made deposits. The scale of technogenesis in mining today is comparable to the results of geological activity that took place over many millions of years. Therefore, even at the early stages of studying the EGC MD, it is necessary to understand the dynamics of changes in the EGC in order to provide preliminary protective measures. Purpose of work. Consideration of striking examples of the dynamics of the EGC MD (from exploration to development), in order to provide methods for managing these changes. Methodology. The article considers the stages of obtaining engineering and geological information for the period of MD operation, which will solve the problems of rational use of the subsoil and protection of the geological environment. Results. For example, the number of objects marked all the stages of learning to yoke the dynamics of their changes, which led to the formation of engineering-geological processes that adversely affect the further testing of MD. Summary. The reaction of the geological environment in the development of MD is not long in coming and is expressed in the development of large-scale engineering and geological processes, which often do not allow further development of MD and threaten people's lives. Therefore, even at the early stages of studying the EGC MD, it is necessary to understand the dynamics of changes in the EGC in order to provide preliminary protective measures.

scholarly journals GEOARKEOLOGI CEKUNGAN SOA, FLORES, NUSA TENGGARA TIMUR

Siddhayatra ◽  
2019 ◽  
Vol 23 (1) ◽  
pp. 31
Author(s):  
Fadhlan Syuaib Intan
Keyword(s):  
Normal Fault ◽  
Geological Structure ◽  
Raw Material ◽  
Alluvial Deposits ◽  
Fault Type ◽  
Geological Conditions ◽  
Geological Information ◽  
Surrounding Areas ◽  
Field Data Analysis ◽  
Surface Geology

Cekungan Soa yang termasuk wilayah Kabupaten Ngada dan Kabupaten Nagekeo terletak di Pulau Flores, banyak menyimpan tinggalan budaya yang antara lain berasal dari masa Paleolitik, yang selama ini belum terlalu diperhatikan oleh peneliti lingkungan, khususnya geoarkeologi. Hal inilah yang menjadi pokok permasalahan yang mencakup kondisi geologi secara umum. Adapun maksud penelitian ini adalah melakukan pemetaan geologi permukaan secara umum sebagai salah satu upaya menyajikan informasi geologi terkait dengan situs arkeologi. Tujuannya adalah untuk mengetahui aspek-aspek geomorfologi, stratigrafi di situs-situs arkeologi. Metode penelitian dilakukan melalui kajian pustaka, survei, analisis data lapangan dan interpretasi. Pengamatan lingkungan memberikan informasi tentang bentang alam daerah penelitian yang terdiri dari satuan morfologi dataran, dan satuan morfologi bergelombang lemah. Sungainya berpola aliran centripetal, berstadia Sungai Dewasa-Tua, sungai tua, Sungai Periodik/Permanen, dan Sungai Episodik/Intermittent. Batuan penyusun adalah breksi vulkanik, tufa, konglomerat, dan endapan aluvial. Struktur geologi berupa patahan dari jenis patahan normal. Eksplorasi di Cekungan Soa telah mendata 12 situs paleolitik. Dari klasifikasi petrologi, alat-alat litik terbuat dari batuan jasper, chert, andesit, dan basal. Batuan sebagai bahan baku alat litik, banyak ditemukan di Cekungan Soa dan sekitarnya, baik dalam bentuk singkapan maupun boulder. Kata kunci: geologi, plistosen, paleolitik, situs terbuka, bahan alat litikSoa Basin, which belongs to Ngada Regency and Nagekeo Regency, is located on Flores Island, with many cultural stays, among others, from the Paleolithic period, which has not been too concerned by environmental researchers, especially geoarkeology. This is the issue that covers general geological conditions. The purpose of this research is to mapping the surface geology in general as an effort to present geological information related to archeological site. The aim is to know the geomorphological, stratigraphic aspects of the archaeological sites. The research method is done through literature review, survey, field data analysis and interpretation. Environmental observations provide information on the landscape of the study area consisting of terrestrial morphology units, and weak wavy morphology units. The river is centripetal flow pattern, with the old river, mature-old river, periodic/permanent river, and episodik /intermittent river. Constituent rocks are volcanic breccias, tuffs, conglomerates, and alluvial deposits. The geological structure is a fracture of the normal fault type. Exploration in the Soa Basin has listed 12 paleolithic sites. From the classification of petrology, litik tools made of jasper, chert, andesite, and basalt rocks. Rock as a raw material litik, found in Soa Basin and surrounding areas, both in the form of outcrops and boulder. Keywords: geology, pleistocene, paleolithic, open site, lithic tools materials

Sign in / Sign up

Export Citation Format

Share Document