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1

A Method of Optimal Design for the Base Network in Structural Deformation Monitoring at Song Hinh Hydroelectricity, Vietnam

Pham Quoc Khanh

Inżynieria Mineralna

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2022

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no. 2

13--20

EN

The article mentions a method of optimal design for the base network in horizontal displacement monitoring at hydroelectric works, based on the average residual level of the measured values. When the target function is the weakest positional error, the obtained result after optimizing is the unique plan that no depends on the designers and their experience. Thus, this is helpful for the production units because they no need to have experts in designing the network. Experiment for the base network of deformation monitoring at Song Hinh hydroelectricity shows that 44%, 50% and 60% of the initial measurement can be reduced when the average residual level is chosen 0.5, 0.4 and 0.3, respectively. The weakest position error of the network after optimizing is 2.4 mm, 2.5 mm and 2.6 mm, respectively, all are smaller than requirement ±3.6mm. This method is mainly applied for the side-angle network that was measured by total station, without considering the optimal design network in the priority direction.

PL

W artykule przedstawiono metodę optymalnego projektowania sieci bazowej w monitoringu przemieszczeń poziomych elektrowni wodnych na podstawie średniego poziomu rezydualnego zmierzonych wartości. Gdy funkcją docelową jest najsłabszy błąd pozycjonowania, uzyskany wynik po optymalizacji jest unikalnym planem, który nie zależy od projektantów i ich doświadczenia. Jest to więc pomocne dla jednostek produkcyjnych, ponieważ nie potrzebują one ekspertów do projektowania sieci. Eksperyment dla podstawowej sieci monitorowania deformacji w elektrowni wodnej Song Hinh pokazuje, że 44%, 50% i 60% początkowego pomiaru można zmniejszyć, gdy średni poziom pozostałości zostanie wybrany odpowiednio 0,5, 0,4 i 0,3. Najsłabszy błąd pozycji sieci po optymalizacji wynosi odpowiednio 2,4 mm, 2,5 mm i 2,6 mm, wszystkie są mniejsze niż wymagane ±3,6 mm. Metodę tę stosuje się głównie dla sieci kątów bocznych, które zostały zmierzone przez tachimetr, bez uwzględnienia optymalnej sieci projektowej w kierunku pierwszeństwa.

2

Research the Integration of Geodetic and Geotechnical Methods in Monitoring the Horizontal Displacement of Diaphragm Walls

Pham Quoc Khanh, Tran Ngoc Dong, Nguyen Thi Kim Thanh, Pham Van Chung

Inżynieria Mineralna

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2021

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no. 2

331--340

EN

This article investigates the integration of geodetic and geotechnical methods for monitoring the horizontal displacement of diaphragm walls. The results show that when the horizontal displacement is measured by the geotechnical method using an inclinometer sensor, the center point at the bottom of the guide pipe is usually chosen to be the origin to calculate displacements of the upper points. However, it is challenging to survey the bottom point for checking its stability directly. If this bottom point moves, the observation results will be incorrect. Thus, the guide pipe must be installed in the stable rock layer. But in the soft ground, this rock layer locates more deeply than the diaphragm walls, so the guide pipe cannot be laid out at the required location. Geodetic methods can directly observe the displacement of the center point on the top of the guide pipe with absolute displacement values at high accuracy. Because the displacements of observation points are determined at stable benchmarks, these values are considered the pipe's displacement. Thus, an integrated solution allows the center point on the top of the pipe to be the origin to calculate the displacements of different points located inside the diaphragm wall. Then, the calculated values are calibrated back to the inclinometer observed values to achieve highly reliable displacement, which reflects the moving of diaphragm walls. An experiment integrating the geodetic and geotechnical methods is conducted with an observation point at a depth of 20 meters at a construction site in Ho Chi Minh city. The deviations of the top point that are observed by the two methods are -4.37 millimeters and -3.69 millimeters on the X-axis and the Y-axis, respectively. The corrected observed results prove that the integrated solution has a good efficiency in monitoring the horizontal displacement of diaphragm walls. The bottom point observed by an inclinometer is unconfident enough to choose to be a reference point.

3

Kod QR zamiast osnowy

Woźniak Marek, Czekaj Damian

Geodeta : magazyn geoinformacyjny

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2021

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nr 8

24--27

4

Research and development work carried out by the Chair of Engineering Geodesy and Measurement and Control Systems, Faculty of Geodesy and Cartography WUT - thematic scope and achievements

Nowak E., Malarski R., Prószyński W., Sadowska A., Woźniak M., Zaczek-Peplinska J.

Reports on Geodesy and Geoinformatics

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2016

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Vol. 100

201--219

EN

Geodetic engineering surveys are an important part of the works carried out by the Faculty of Geodesy and Cartography, Warsaw University of Technology. These works concern measurement techniques as well as advanced result analysis methods applied in precise industrial surveys and in processes controlling object’s behaviour over time. The thematic scope of research realised by Chair of Engineering Geodesy and Control-Measuring Systems shows that article related to geodetic engineering measurements and geodetic monitoring is carried out with high intensity, resulting in technological advancement and implementation of new or improved measurement solutions and methods of measurement result development.

5

Laser scanning in engineering surveying : methods of measurement and modeling of structures

Lenda G., Uznański A., Strach M., Lewińska P.

Reports on Geodesy and Geoinformatics

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2016

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Vol. 100

109--130

EN

The study is devoted to the uses of laser scanning in the field of engineering surveying. It is currently one of the main trends of research which is developed at the Department of Engineering Surveying and Civil Engineering at the Faculty of Mining Surveying and Environmental Engineering of AGH University of Science and Technology in Krakow. They mainly relate to the issues associated with tower and shell structures, infrastructure of rail routes, or development of digital elevation models for a wide range of applications. These issues often require the use of a variety of scanning techniques (stationary, mobile), but the differences also regard the planning of measurement stations and methods of merging point clouds. Significant differences appear during the analysis of point clouds, especially when modeling objects. Analysis of the selected parameters is already possible basing on ad hoc measurements carried out on a point cloud. However, only the construction of three-dimensional models provides complete information about the shape of structures, allows to perform the analysis in any place and reduces the amount of the stored data. Some structures can be modeled in the form of simple axes, sections, or solids, for others it becomes necessary to create sophisticated models of surfaces, depicting local deformations. The examples selected for the study allow to assess the scope of measurement and office work for a variety of uses related to the issue set forth in the title of this study. Additionally, the latest, forward-looking technology was presented - laser scanning performed from Unmanned Aerial Vehicles (drones). Currently, it is basically in the prototype phase, but it might be expected to make a significant progress in numerous applications in the field of engineering surveying.

6

Vessel traffic monitoring and information system; reasons of establishing and principles of operation

Urbański J., Morgaś W., Kopacz Z.

Reports on Geodesy

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2007

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z. 1/82

359-366

EN

In this paper, an attempt has been made to present and discuss the main issues of the Vessel Traffic, Monitoring and Information System (VTMIS). The VTMIS is the regional system being now developed by the European Union for its maritime areas. The main objective of this System is to ensure the proper level of maritime safety and antiterrorist security.

7

Verification of railroad track height measurement methods based on statistic elaboration of the results

Owerko T., Strach M.

Reports on Geodesy

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2007

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z. 1/82

233-242

8

The suitability of angle measurements made with steep targets for determining spatial positions of points

Odziemczyk W.

Reports on Geodesy

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2007

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z. 1/82

217-223

9

The problem of validity of benchmark elevations for general engineering tasks in urbanised areas on the example of vertical benchmark network in the city of Wroclaw

Grzempowski P., Mąkolski K.

Reports on Geodesy

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2007

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z. 1/82

91-101

EN

To carry out many surveying operations, one requires, apart from location determined in horizontal plane also elevation of selected points in a project. In the case of work realised over a large area, particularly if the object to be measured is of elongated shape, these tasks are performed in relation to a greater number of national network benchmarks. At that point control of benchmarks locations in relation to one another and determination of the most reliable reference frame for surveying tasks are required. The need to carry out such control will be proved in this paper on the example of historical changes of benchmark ordinates of vertical network in the city of Wroclaw.

10

The influence of gradient filters and edging algorithms on defining accuracy of the position of a measured edge of the code element in testing the metricity of levelling code graduation, based on the analysis of raster image

Jastrzębski S.

Reports on Geodesy

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2007

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z. 1/82

117-122

11

The hopfield neural network in the aspect of the stabilization of the displacement phenomenon

Gil J., Mrówczyńska M.

Reports on Geodesy

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2007

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z. 1/82

75-80

12

The georadar method: an assessment of efficiency of subsurface conduits position determination on selected test fields

Ortyl Ł., Sołtys M.

Reports on Geodesy

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2007

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z. 1/82

225-232

EN

The paper presents results of georadar positioning of a set of subsurface conduits, together with an assessment of efficiency of their detection. The measurements on test fields were performed with the RAMAC/GPR georadar, produced in Sweden by the Mala GeoScience Company. Numerous radargrams were properly processed with an optimal filtering sequence, aimed at production of a readable image of the detected conduits. The results were assessed also from the efficiency point of view of the subsurface structure detection method. The phenomenon of signal polarization, which helps to distinguish metallic and plastic conduits, is also discussed. Elements of surveying and computational procedures, leading to completion of content of digital thematic maps by the georadar sensing integrated with GPS positioning, are also given.

13

The feasibility of applying automatic target recognition in trigonometric levelling

Próchniewicz D., Szpunar R., Walo J., Pachuta A.

Reports on Geodesy

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2007

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z. 1/82

267-273

EN

The obtained results of the field experiments fully confirmed the feasibility of applying ATR systems in trigonometric levelling. In the tested span experiment at Józefosław, the value difference of height differences obtained with precise geometric levelling and the mean value of all measurements differed by a mere 2.7 mm, and for midnight measurements - it did not exceed 1 mm. The measurements made in the Pieniny Range were also successful in the case of observation compatibility and limiting the impact of atmospheric refraction on measurement results. Unfortunately, the comparison of the obtained height differences with those of 5 years ago showed considerable discrepancies stemming from benchmark subsiding rather than technological accuracy of trigonometric levelling. To verify this thesis it is planned to repeat trigonometric measurements on the testing ground in the Pieniny and to carry out control measurements by means of precise geometric levelling. Summing up, one can note that the use of tacheometers along with ATR enables to automate measurements and related quasi-continuous observations. These traits enable moreover: - to increase the number of observations, and what follows, increase accuracy and reliability of the zenithal length determined, - to average measurements made over a long period, which enables to undermine the influence of atmospheric refraction on the value of height difference measured, - to make observations in different atmospheric conditions, including nighttime when the atmosphere is stable, - to eliminate personal errors of the observer, - to analyze conducted observations in real time.

14

The evaluation of geometric changes in special type structures by surveying methods on the example of the Spodek Dome in Katowice

Szczerbowski Z.

Reports on Geodesy

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2007

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z. 1/82

326-335

EN

The paper presents an example of surveying field works carried in the main hall of The Entertainment-Sport Hall in Katowice. Both the technology and program of surveying were determined by the main goal that was an evaluation of the main hall construction performance and enablement of periodic observations for displacement evaluation in future. The individuality of presented survey results analysis relates to the structure characteristic and knowingness about primary geometry properties of the construction that was affected by mining.

15

Testing the constancy of the target axis with a change in focusing in precise theodolites and electronic tacheometers

Odziemczyk W.

Reports on Geodesy

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2007

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z. 1/82

211-216

EN

The obtained measurement results show that for short targets of a few metres long, position changes of the target axis are considerable and even come close to lc (TC1610). Even in the case of the telescopes of precise T 2002 theodolites geared for close object measurements, target axis vacillations almost amount to 40cc. The course of vertical changes in the target axis vacillations is quite distinctive/typical/unusual/interesting? For all tested instruments the character of these changes was very similar. It is a phenomenon which is difficult to explain in a clear fashion. It should be also noted that the greatest changes take place with short targets up to about 10 m. Vacillations of the target axis above this length are considerably smaller and generally do not exceed 10cc. Although target axis movements expressed in terms of angular units are significant, their influence on accurate location of a point position is slight and does not exceed (especially for the horizontal component) a few hundredths millimeters. In spite of this changes in the target axis should be taken into consideration in designing high precision angular measurements for small objects.

16

Terrestrial laser system testing using reference bodies

Kopacik A

Reports on Geodesy

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2007

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z. 1/82

135-143

17

Serviceability problem of levelling networks based on the example of Bydgoszcz network

Derezińska A., Kujawski E.

Reports on Geodesy

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2007

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z. 1/82

55-59

18

Scientific expeditions to Svalbard, organized by the Faculty of Geodesy and Cartography, the Warsaw University of Technology (WUT)

Pachuta A., Walo J., Adamek A., Woźniak M., Rajner M., Węzka K., Próchniewicz D

Reports on Geodesy

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2007

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z. 1/82

243-250

19

Role of engineering geodesy in ensuring safety of engineering constructions - general approach

Ney B.

Reports on Geodesy

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2007

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z. 1/82

199-201

20

Results of the first GPS measurement campaign for the determination of absolute vertical and horizontal deformations in the Main and Old City of Gdansk

Baryła R., Oszczak S., Wielgosz P., Bakuła M., Cellmer S., Popielarczyk D., Jarmołowski W., Tyszko A., Oszczak B., Gregorczyk R., Rapiński J., Zapert M.

Reports on Geodesy

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2007

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z. 1/82

25-31

EN

The results of GPS static measurements, conducted in the first measurement campaign at the reference and check points should be adopted as the values of reference for future observation results. The measurement procedures, developed for the first campaign, should be followed in further measurements. The measurement equipment (pole for forced centring of a GPS aerial, GPS aerial, GPS receiver) assigned to each point during the first campaign, should be used each time at the check points. The same calculation procedure should be followed in the analysis of the GPS observation data in future measurement campaigns. If the need to change the calculation procedure is justified, the calculations from previous measurement campaigns should be absolutely redone.