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Seismic velocity of P-waves to evaluate strength of stabilized soil for Svenska Cellulosa Aktiebolaget Biorefinery Östrand AB, Timrå

Lindh Per, Lemenkova Polina

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 4

art. no. e141593

EN

Evaluating soil strength by geophysical methods using P-waves was undertaken in this study to assess the effects of changed binder ratios on stabilization and compression characteristics. The materials included dredged sediments collected in the seabed of Timrå region, north Sweden. The Portland cement (Basement CEM II/A-V, SS EN 197-1) and ground granulated blast furnace slag (GGBFS) were used as stabilizers. The experiments were performed on behalf of the Svenska Cellulosa Aktiebolaget (SCA) Biorefinery Östrand AB pulp mill. Quantity of binder included 150, 120 and 100 kg. The properties of soil were evaluated after 28, 42, 43, 70, 71 and 85 days of curing using applied geophysical methods of measuring the travel time of primary wave propagation. The P-waves were determined to evaluate the strength of stabilized soils. The results demonstrated variation of P-waves velocity depending on stabilizing agent and curing time in various ratios: Low water/High binder (LW/HB), High water/Low binder (HW/LB) and percentage of agents (CEM II/A-V/GGBFS) as 30%/70%, 50%/50% and 70%/30%. The compression characteristics of soils were assessed using uniaxial compressive strength (UCS). The P-wave velocities were higher for samples stabilized with LW/HB compared to those with HW/LB. The primary wave propagation increased over curing time for all stabilized mixes along with the increased UCS, which proves a tight correlation with the increased strength of soil solidified by the agents. Increased water ratio gives a lower strength by maintained amount of binder and vice versa.

2

Dynamic elastic properties of the hard coal seam at a depth of around 1260 m

Krawiec Krzysztof

Gospodarka Surowcami Mineralnymi

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2021

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T. 37, z. 3

159--176

EN

The knowledge of the dynamic elastic properties of a coal seam is important in the context of various types of calculations of the seam behavior under various stress-strain conditions. These properties are often used in numerical and analytical modeling related to maintaining the stability of excavations and the analysis of mechanisms, e.g. related to the risk of rock bursts. Additionally, during the implementation of seismic surveys, e.g. seismic profiling and seismic tomography in coal seams, the reference values of the elastic properties of coal are used in the calculation of relative stresses in various geological and mining conditions. The study aims to calculate the dynamic elastic parameters of the coal seam located at a depth of 1,260 m in one of the hard coal mines in the Upper Silesian Coal Basin (USCB). Basic measurements of the velocity of P- and S-waves were conducted using the seismic profiling method. These surveys are unique due to the lack of the velocity wave values in the coal seam at such a great depth in the USBC and difficult measurement conditions in a coal mine. As a result, dynamic modulus of elasticity was calculated, such as Young’s modulus, volumetric strain modulus, shear modulus and Poisson’s ratio. The volumetric density of coal used for calculations was determined on the basis of laboratory tests on samples taken in the area of the study. The research results showed that the calculated mean P-wave velocity of 2,356 m/s for the depth of 1,260 m is approximately consistent with the empirical relationship obtained by an earlier study. The P-wave velocity can be taken as the reference velocity at a depth of approx. 1,260 m in the calculation of the seismic anomaly in the seismic profiling method.

PL

Znajomość dynamicznych właściwości sprężystych pokładu węgla jest istotna w kontekście różnego rodzaju obliczeń zachowania się pokładu w różnorakich warunkach naprężeniowo-odkształceniowych. Właściwości te są często wykorzystywane w modelowaniach numerycznych i analitycznych związanych z utrzymaniem stateczności wyrobisk oraz analizą mechanizmów, np. związanych z zagrożeniem tąpaniami. Dodatkowo w trakcie realizacji badań sejsmicznych np. profilowań sejsmicznych i tomografii sejsmicznej w pokładach węgla referencyjne wartości właściwości sprężyste węgla wykorzystywane są w obliczaniach naprężeń względnych w różnych warunkach geologiczno-górniczych. Celem badań jest obliczenie dynamicznych sprężystych parametrów pokładu węgla, położonego na głębokości około 1260 m, w jednej z kopalń węgla kamiennego w Górnośląskim Zagłębiu Węglowym. Podstawowe pomiary prędkości fal sejsmicznych wykonano metodą profilowania sejsmicznego. Te pomiary są unikatowe ze względu na dużą głębokość położenia profilu pomiarowego oraz trudne warunki pomiarowe w kopalni. W efekcie obliczono dynamiczne moduły sprężystości takie jak: moduł Younga, moduł odkształcenia objętościowego, moduł odkształcenia postaciowego oraz współczynnik Poissona. Gęstość objętościową węgla przyjętą do obliczeń wyznaczono na podstawie testów laboratoryjnych na próbach pobranych w rejonie badań. Wyniki badań pokazały, że obliczona średnia prędkość fali P równa 2356 m/s dla głębokości 1260 m jest w przybliżeniu zgodna z empirycznymi zależnościami określonymi we wcześniejszych badaniach. Prędkość fali P może być przyjęta jako prędkość odniesienia na głębokości około 1260 m w obliczeniach anomalii sejsmicznej w metodzie profilowania sejsmicznego.

3

2D multi parameter waveform inversion of land refection seismic data obtained from the particle motion response from the vertical geophone

Li Qingyang, Wu Guochen

Acta Geophysica

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2020

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Vol. 68, no. 2

377--388

EN

Onshore seismic exploration analyzes seismic wave propagation in elastic media, which includes the conversion between P- and S-waves. The development of multi-wave and multi-component seismic exploration methods provides data that enable onshore elastic wave full-waveform inversion. However, most data sets of onshore exploration are single component obtained from the particle-motion response from the vertical geophone. When the aiming area has a low-velocity zone, the ray path of refected wave that propagates to the detector is nearly perpendicular to the ground surface, so that we call it P-wave data. In this paper, we focus on multi-parameter waveform inversion using P-wave refection seismic data. Although only P-wave data are received, it still contains the converted P-wave information, and the converted P-wave energy gradually increases as the ofset increases. As seismic acquisition technology, observation systems and science develop, the folds and acquisition ofset increase signifcantly, and the seismic data contain important converted P-wave information. In this paper, the frst-order elastic velocity–stress equation is decomposed to obtain the scalar-P-wave equation from which the S-wave velocity is included frstly. Then we present the theoretical framework for onshore multi-parameter full-waveform inversion using P-wave data. In order to explore the inversion potential of the P-wave data (extracting the S-wave velocity from the converted P-wave information) and accuracy and stability of the P- and S-wave velocity inverted by our method, we carry out numerical tests via diferent inversion strategies, by using the P-wave data regarded as containing converted P-wave information, and get successful results.

4

Verification of the seismic P‑wave velocities under Moho boundary: Central Poland case study, LUMP profile

Dec Monika, Polkowski Marcin, Janik Tomasz, Stec Krystyna, Grad Marek

Acta Geophysica

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2019

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Vol. 67, no. 1

41--57

EN

The tectonic settings investigated by several seismic projects in previous research targeting the structure in Central Poland mainly focused on the Earth’s crust. In this paper, we present P-wave velocity verification in the uppermost mantle beneath LUMP profile towards SSE-NNW. Using recordings of 36 DATA-CUBE recorders from ca. 300–490 km far earthquake in coal mine “Janina” in southern Poland, we calculated travel times to verify P-wave velocity below the Moho boundary from previous studies. It shows that a significantly lower mean velocity value should be used for the upper mantle while counting these offsets of travel times in the SSE-NNW direction than that used on previous profiles. We present two possible models: first, the most simple one that fits the observed first arrivals, and the second with a low-velocity layer beneath the Moho boundary. In both cases, we used a priori crustal model focusing only on P-wave velocity in the uppermost mantle. Both of them significantly improved adjustment of travel times to the observed data. To evaluate the tendency of adopting too high velocities beneath the Moho, we used also 11 broadband stations, Reftek 151-121 “Observer”, from “13 BB Star” passive experiment and 6 STS-2 seismometers from permanent stations of the Polish Seismological Network (PLSN).

5

Sejsmiczna ocena spękania górotworu karbońskiego w rejonach płytkiej działalności górniczej

Dec J.

Geologia / Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie

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2009

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T. 35, z. 2/1

405-412

EN

Results of seismic investigations are presented in this paper. Investigation were carried out in regions of shallow coal exploitation. In those regions we can observe strongly disturbed zones. In such case seismic measurements show the strong velocity anomalies. Velocity of seismic P wave strongly depends on the cracks density. As a results of investigation a relationship between RQD (Rock Quality Designation), cracks density and P wave velocity is shown. Quality index QI is the best estimator of the real Carboniferous rock mass destruction. As a final result the seismic scale of the Carboniferous rocks evaluation is proposed.

6

Wpływ obecności iłów, porowatości oraz nasycenia porów wodą i gazem na parametry sprężyste skał zbiornikowych określanych na podstawie teoretycznych modeli ośrodków porowatych i danych geofizyki wiertniczej

Bała M.

Przegląd Geologiczny

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2007

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Vol. 55, nr 1

46-46

EN

The paper describes effects of shale content, porosity and water- and gas saturation on elastic parameters of rocks. The analysis was based on theoretical relationships for porous media, known as the Biot-Gassmann's and Kuster and Toksöz's models, and on Raymer-Hunt-Gardner formulas. Well-logging data and results of the quantitative interpretation of well logs were also analysed. The relationships between P-wave and S-wave velocities and reservoir parameters may contribute to solving some problems associated with seismic interpretation of wave forms in Miocene gas deposits in the Carpathian Foredeep.

7

Dyskretna pamięć maksymalnych temperatur w skałach osadowych w przebiegu emisji sejsmoakustycznej i prędkości fali podłużnej

Zuberek W.M., Żogała B.

Geologia / Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie

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1999

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T. 25, z. 1

15-24

PL

Przedstawiono wyniki badań nad cyklicznym podgrzewaniem próbek karbońskich piaskowców i mulowców. Podczas kilku cykli podgrzewań od ok. 30 stopni Celsjusza do ok. 200 stopni Celsjusza mierzono emisję sejsmoakustyczną i czas propagacji fal podłużnych. Badania potwierdziły występowanie efektu pamięci maksymalnej temperatury w przebiegu emisji sejsmoakustycznej i pamięci prędkości fali P oraz, że efekty te stopniowo zanikają z upływem czasu. Zaobserwowane zmiany średnich wartości współczynnika pamięci termicznej B, skumulowanej liczby zliczeń emisji sejsmoakustycznej N/z oraz prędkości fali P dobrze korelują się ze sobą

EN

The results of the cyclic heating of carboniferous sandstone and mudstone samples are presented. The several heating cycles from approximately 30 degrees of Celsius up to 200 degrees of Celsius were done and the measurements of acoustic emission activity and P-wave velocity were realised. The research confirmed that the maximum temperature memory effect in AE and P-wave velocity exists and the effect gradually decays with time. Changes of the average values of thermal memory coefficient B, AE cumulated count number N/z and P-wave velocity correlate well with each other