scholarly journals Monitoring Vertical Displacements by Precise Levelling: A 31- Years Case Study in Duhok Dam

2020 ◽  
Vol 23 (2) ◽  
pp. 800-808
Author(s):  
Sarmad Salim ◽  
◽  
Sarhat Adam ◽  
Keyword(s):  
Precise Levelling ◽  
Vertical Displacements

scholarly journals HEIGHT DETERMINATION TECHNIQUES FOR THE NEXT NATIONAL HEIGHT SYSTEM OF FINLAND - A CASE STUDY

2015 ◽  
Vol 41 (4) ◽  
pp. 145-155
Author(s):  
Timo Saari ◽  
Markku Poutanen ◽  
Veikko Saaranen ◽  
Harri Kaartinen ◽  
Antero Kukko ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Pilot Project ◽  
Satellite System ◽  
Reference Station ◽  
Virtual Reference ◽  
Precise Levelling ◽  
Height Determination ◽  
Weak Points ◽  
Global Navigation Satellite

Precise levelling is known for its accuracy and reliability in height determination, but the process itself is slow, laborious and expensive. We have started a project to study methods for height determination that could decrease the creation time of national height systems without losing the accuracy and reliability that is needed for them. In the pilot project described here, we study some of the alternative techniques with a pilot field test where we compared them with the precise levelling. The purpose of the test is not to evaluate the mutual superiority or suitability of the techniques, but to establish the background for a larger test and to find strong and weak points of each technique. The techniques chosen for this study were precise levelling, Mobile Laser Scanning (MLS) and Global Navigation Satellite System (GNSS) levelling, which included static Global Positioning System (GPS) and Virtual Reference Station (VRS) measurements. This research highlighted the differences of the studied techniques and gave insights about the framework and procedure for the later experiments. The research will continue in a larger scale, where the suitability of the techniques regarding the height systems is to be determined.

Comparison of Numerical Methods for Determining Torsion Stiffness of Automotive Chassis

2011 ◽  
Author(s):  
Steven Tebby ◽  
Ebrahim Esmailzadeh ◽  
Ahmad Barari
Keyword(s):  
Finite Element Analysis ◽  
Analytical Approach ◽  
Torsional Stiffness ◽  
Design Stage ◽  
Element Analysis ◽  
Detailed Design ◽  
Vertical Displacements ◽  
Comparison Of The Results ◽  
Torsion Stiffness

The torsion stiffness of an automotive chassis can be determined using an analytical approach based purely on geometry, using an experimental method, or alternatively by employing a Finite Element Analysis (FEA) process. These three methods are suitable at different design stages and combined together could prove to be practical methods of determining the torsion stiffness of a chassis. This paper describes and compares two distinct FEA processes to determine the torsion stiffness of an automotive chassis during the detailed design stage. The first process iteratively applies forces to the model and records displacements, while the second process gradually applies vertical displacements in place of force to determine the torsional stiffness threshold. Each method is explained and supported with a case study to provide a basis of comparison of the results.

scholarly journals Adjusting the Influence Function Method for Subsidence Prediction

2013 ◽  
Vol 553 ◽  
pp. 59-66 ◽  
Author(s):  
Ali Saeidi ◽  
Olivier Deck ◽  
Marwan Al Heib ◽  
Thierry Verdel ◽  
Alain Rouleau
Keyword(s):  
Efficient Method ◽  
Influence Function ◽  
Function Method ◽  
Underground Mining ◽  
Building Damage ◽  
Ground Movement ◽  
Ground Movements ◽  
Influence Function Method ◽  
Vertical Displacements

Theextraction of ore and minerals by underground mining may induce groundsubsidence phenomena. These phenomena produce several types of ground movement likehorizontal and vertical displacements, ground curvature and horizontal groundstrain at the surface, and associated building damage in urban regions. Theinfluence function is a well-known and efficient method for the prediction ofthese movements, but its application is restricted to mining configurationswith the same influence angle around the mine. However, this angle may displaydifferent values when the mine is not horizontal or when other subsidenceevents already occurred near the considered mine.In this paper a methodology and analgorithm are developed, based on the traditional influence function method inorder to take into account different influence angles. This methodology isimplemented in the Mathematicasoftware and a case study is presented with data from the Lorraine iron minefield in France. Ground movements calculated with the developed methodologyshow a fair concordance with observed data.

scholarly journals Numerical analysis of geogrid contribution to railway track reinforcement

2018 ◽  
Vol 211 ◽  
pp. 12006
Author(s):  
António Lanca ◽  
Zuzana Dimitrovová ◽  
Madalena Barroso ◽  
Simona Fontul
Keyword(s):  
Added Value ◽  
Railway Track ◽  
Railway Network ◽  
Vertical Displacements ◽  
Downward Propagation ◽  
Long Term Performance ◽  
Term Performance ◽  
Lateral Deformations

In this work, influence of geogrids on overall stabilization of railway tracks is studied numerically. It is expected that by geogrids implementation significant reduction in the downward propagation of stresses will be obtained, which consequently should assure more resilient long-term performance. In this first approach, however, only added value to the confinement level of the ballast layer is analysed, by evaluation of lateral deformations. A case study is related to a part of the Portuguese railway network. The track and the passing vehicle are modelled in commercial explicit dynamics software LS-DYNA. Firstly, the model is validated by comparison with experimental data. Then a fictitious scenario of the same track with a deteriorated region which is further rehabilitated by the geogrid placement is analysed. Different situations are compared in terms of lateral and vertical displacements at several levels, but for simplicity only rail deflections are shown here.

Determining dislocation love number of vertical displacement using GPS observations: case study of 2011 Tohoku-Oki earthquake (Mw 9.0)

2020 ◽  
Vol 222 (2) ◽  
pp. 965-977
Author(s):  
Junyan Yang ◽  
Wenke Sun
Keyword(s):  
Green's Functions ◽  
Green’S Functions ◽  
Vertical Displacement ◽  
Fault Slip ◽  
Earth Model ◽  
Love Number ◽  
The Earth ◽  
Love Numbers ◽  
Vertical Displacements

SUMMARY The concept of determining the dislocation Love numbers using GNSS (Global Navigation Satellite System) data and calculating the corresponding Green's functions is presented in this paper. As a case study, we derive the dislocation Love number h of vertical displacement by combining 1232 onshore GPS data and 7 GPS-Acoustic data with the 2011 Tohoku-Oki earthquake (Mw 9.0). Three fault-slip distributions are used to compare and verify the theory and results. As the GPS stations are only located in Japan Island and along the Japan trench, we use the theoretical vertical displacements of a spherically layered Earth structure to constrain the low-order signal. The L-curve and an a priori preliminary reference skill are applied in the inversion method. Then, the GPS-observed vertical displacement changes are used to invert for the vertical displacement dislocation Love numbers h based on three different fault-slip models. Our results indicate that the estimated dislocation Love numbers $h$ fluctuate significantly from the earth model (i.e. the preliminary reference earth model), especially for the $h_{n1}^{32}$ component, and these changes in $h_{n2}^{12}$ and $h_{n0}^{33} - h_{n0}^{22}$ are relatively small. The vertical displacements derived from the inversion results agree well with the GPS vertical observations. The inverted dislocation Love numbers are considered to profile the regional structure which differs from the mean 1-D heterogeneous structure of the Earth, and the corresponding Green's functions of four independent dislocation sources describe a more reasonable seismic deformation field.

scholarly journals PRECISE LEVELLING DATA PROCESSING NEAR TERRACED LANDFORMS

2014 ◽  
Vol 40 (2) ◽  
pp. 51-57
Author(s):  
Silja Talvik
Keyword(s):  
Data Processing ◽  
Gravity Field ◽  
Field Gradient ◽  
Information Needs ◽  
Gravity Data ◽  
Precise Levelling ◽  
The North ◽  
Gravity Database ◽  
The Given

Precise levelling results are affected by the Earth’s gravity field, especially in areas of abrupt changes of landscape, such as terraced landforms. To eliminate the effect of the gravity field gradient, corrections need to be used in precise levelling data processing. To estimate the expected range of the correction due to the gravity field gradient (here called the gravimetric correction) within a region of terraced landforms, an experiment was proceeded in Estonia. Gravity data together with GNSS coordinates were acquired in 2011 in an area where a levelling section crosses the North Estonian Klint (height difference of 30 m within the levelling section). The gravimetric correction for the given 300 m long section proved to be 1.2 mm. Practically the same correction value can be obtained using interpolation of existing gravity data. However, in the case study area the gravity database had an extremely good quality which may not be the case elsewhere in which case gravimetric information needs to be collected alongside levelling. In height network calculations it is important to note that in such challenging areas all points should obtain their height values from an adjustment or from a point on the same side of a terrace, otherwise errors in heights may be as large as the gravimetric correction across the terrace.

scholarly journals Investigating the vertical displacement of Duhok embankment Dam: A 31- Years Case Study

2021 ◽  
Vol 9 (ICRIE) ◽  
Author(s):  
Sarmad Abdullah M.Salim ◽  
◽  
Sarhat Mustafa Adam ◽  
Keyword(s):  
Vertical Displacement ◽  
Vertical Movement ◽  
Embankment Dam ◽  
The West ◽  
Monitoring Point ◽  
Downward Displacement ◽  
Vertical Displacements ◽  
The City

The paper studies the long-term settlement behaviour of more than 30-year of the Duhok dam. The dam uses as the major lake for water supply to the city of Duhok and nearby areas. High-precision levelling was used to measure the deformation of the dam to monitor vertical displacements. Five survey campaigns were conducted over 30-year duration: 1988, March 1990, June 1999, March 2017 and February 2019. Analysis of the results found that the highest downward displacement of roughly 20.4 cm was witnessed between 1988 and 2019 for a monitoring point (BM24) located centrally along the bank of the dam. On the other hand, the highest vertical movement of roughly 1.5 cm was estimated between 1990 and 2019 at the monitoring point (BM27) on the west side of the dam. The monitoring point (BM24) had the highest average absolute movement of about 6.0 mm (per year) over the 31 years. Detailed results and analyzes are presented in this article.

scholarly journals Complex Analysis of the Impact of Construction of an Underground Metro Line on the Urban Environment – a Case Study from the Vistula Valley in Warsaw

2016 ◽  
Author(s):  
Łukasz Kaczmarek
Keyword(s):  
Urban Areas ◽  
Complex Analysis ◽  
Surface Deformation ◽  
Digital Terrain Model ◽  
Terrain Model ◽  
Digital Terrain ◽  
Vertical Displacements ◽  
The Stability ◽  
The Impact

Underground construction in urban areas is a complex investment, impacting existing buildings. The paper presents a case study of the 2nd metro line, in close proximity to the Warsaw Slope (Kaczmarek, Popielski 2016; Kaczmarek et al. 2016). First the digital terrain model was analysed. Next the prospection of electrical resistivity imaging (ERI) were performed. In addition results of archive boreholes were correlated to ERI outcome. Then complementary laboratory tests (e. g. triaxal CU tests) were carried out. Furthermore the prisms located on the Warsaw Slope were measured with tacheometric technique. This results were merged to archive monitoring observations of slope surface deformation and near building settlements. Based on previous steps the finite element method (FEM) simulations were performed. Thanks to numerical analysis cumulative settlements of a particular building above the metro tunnel were calculated. The values of vertical displacements does not affect the stability of the building or the slope nearby. Nevertheless, it can impact serviceability. Furthermore, the value of the calculated Safety Factor of the Warsaw Slope in this section is 1.1. Hence, slope changes require continuous observations. The presented case study shows the usefulness of complex research analysis and its suitability for the purposes of building an extension of the 2nd metro line.

scholarly journals Evaluation of Hypoplastic Clay Model for Deep Excavation Modelling

2016 ◽  
Vol 62 (4) ◽  
Author(s):  
M. Mitew-Czajewska
Keyword(s):  
Accurate Determination ◽  
Deep Excavation ◽  
Element Analysis ◽  
Clay Model ◽  
Modified Cam Clay ◽  
Vertical Displacements ◽  
Cam Clay

AbstractThis paper presents an evaluation of the Hypoplastic Clay constitutive model for finite element analysis of deep excavations and displacements induced by excavations in the influence zone. A detailed description and formulation of the Hypoplastic Clay soil model is included. A parametric case study of a deep excavation executed in Pliocene clays is presented. FE analysis was performed using several soil models (Mohr-Coulomb, Modified Mohr-Coulomb, Drucker-Prager, Modified Cam-Clay, Hypoplastic Clay) and the results were compared to in-situ displacements measurements taken during construction. Final conclusions concerning the suitability of the Hypoplastic Clay model for deep excavation modelling in terms of accurate determination of horizontal displacements of the excavation wall, the uplift of the bottom of excavation, and, most importantly, vertical displacements of the terrain in the vicinity of the excavation are presented.

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