Model essay on engineering survey graduation thesis "Error Analysis of Total Station in Hydraulic Engineering Survey"
Abstract: China's economic development has experienced a high-speed stage, and now it is more and more stable, which puts forward higher requirements for some domestic infrastructure. Therefore, China's water conservancy project construction is also one of the important construction projects in recent years. Therefore, the quality of its hydraulic engineering has been widely recognized, and there are stricter requirements for error analysis and precision control of total station in hydraulic engineering survey, so below we focus on the specific research on error analysis and precision control of total station in hydraulic engineering survey.
Keywords: total station for hydraulic engineering survey
1 preface
Total station is widely used in the survey of water conservancy projects. In hydraulic engineering survey, its accuracy must be guaranteed. In this case, we must use the total station to measure it, which makes the measurement more convenient. Therefore, it is more important to do a good job in error analysis and precision control of total station. We use total station to reduce the precision error in the measurement, and use improved methods to effectively ensure the accuracy of the measurement results. Therefore, in the following, we analyze the measurement error and accuracy of total station in water conservancy projects.
Application of Total Station in Water Conservancy Engineering Survey
When we measure water conservancy projects, total station is widely used, because there are many kinds of instruments used, such as theodolite and level. However, from the comprehensive analysis and the accuracy and practicability of its instruments, the total station has obvious accuracy advantages over other instruments. Total station is portable, accurate and comprehensive. In hydraulic engineering, the requirements for measurement are very high, and the total station can meet the requirements for its measurement accuracy. For some basic survey data used in water conservancy projects, total station can be obtained through measurement, and its accuracy control is high. Especially in the early design stage of water conservancy project, as well as the construction stage in the middle stage of water conservancy project, the maintenance stage and application management in the later stage need total station, and some large-scale water conservancy projects that need to provide high-grade plane control network also need total station.
3 error analysis
3. 1 total station shafting error analysis
The reasons for the errors in the total station measurement are as follows: firstly, the lens of the total station was not installed and corrected before the measurement, and the crosshair in the telescope shifted its center, which directly led to the collimation axis of the total station being not perpendicular to the horizontal axis; The collimation axis will also be affected by temperature and atmospheric refraction, which are the reasons for the error. In addition, due to its positioning error, the shafting error is caused by the errors of vertical axis lateral error compensation, horizontal axis error compensation and collimation axis error compensation.
3.2 Error analysis of instrument panel in the whole station
The reason of dial error lies in its vertical angle, which is influenced by it, so the greater its vertical angle, the greater the error. When we observe it, if our observation direction is on the left side of the dial, then the collimation axis will be on the right or left side of the standard collimation axis. At this time, the error caused by the dial will actually change due to its measured value. If we deal with the transformation circle, then when the observation direction is on its right, the collimation axis is on its left or right, and the drop caused by the collimation axis is opposite to the measurement results on both sides. In the above two cases, the scale value of the error is the same, but the sign of the target is opposite and the value is the same. At this time, we can average the two measured values of the scale. When we ensure that the scanning disk is transported, the direction of the collimation part is the same, so that the horizontal dial error caused by rotation can be produced. If its direction is vertical, we can do it by adjusting the direction and vertical axis of the photoelectric scanning dial, so that the error of half-angle measurement can be reduced or disappeared, and then the error produced by the dial can be reduced. The common ranging errors of total station are mainly adder and multiplier errors and their periodic errors.
3.3 Total Station Ranging Error Analysis
The principle of total station is to determine the distance by measuring the time of carrier wave traveling back and forth at both ends of the survey line by using the carrier wave emitted by the instrument. When we determine the distance measurement, it is difficult to effectively use the aiming function of the total station because the accuracy will be affected by people's own visual reasons. Therefore, it will cause a certain systematic error, which will lead to a certain gap and poor accuracy between people's judgment and measurement results. Because the total station mostly adopts phase mode, the error in measurement will be proportional to the distance produced by measurement. At this time, there will be many reasons for the error, such as atmospheric refraction, temperature, humidity, air pressure and so on. , it will have a certain error in the measurement of total station and have a great impact.
4 precision control and matters needing attention
4. 1 Control the error precision of total station shafting.
The measurement data in hydraulic engineering will change due to the influence of the shafting error of the total station, which makes the whole measurement result have certain errors, so the errors caused by the total station must be controlled. We can reduce the shafting error of the total station by different observation methods, such as replacing the full angle with half angle measurement, and considering the change of the measurement accuracy of the total station. When the total station leaves the factory, its accuracy will have a certain standard, so we will change its observation angle when measuring and using it, which will cause some errors in its longitudinal axis direction and transverse axis direction, or cause errors in the arc shafting of the sector.
4.2 Control the dial error of total station
The actual situation of water conservancy project is combined with its elevation measurement. We use trigonometric leveling method to control the accuracy of total station error, and then calculate its error through its trigonometric elevation, and get the result according to its curvature on the earth, and then calculate it according to the examples generated in the project, and then according to the actual measurement work. This can improve its working efficiency when working outside.
4.3 Control the ranging error of total station
This technology is specially aimed at the limitation caused by the observation environment and the observation ability and resolution of human eyes, which can effectively improve the accuracy of precision error. If you want to reduce the ranging error of total station, you can measure it many times and then take its average value to determine the result.
4.4 Matters needing attention in using total station
When using the total station, we should pay attention to make the total station as close as possible to the central axis of the two measuring points, because the placement position of the total station will affect the accuracy of elevation measurement and the shafting error of the total station. Because the angle of the total station will have a direct impact on the dial difference of the total station, it is necessary to ensure the accuracy of the vertical angle of the observation target. It is necessary to choose a suitable ranging position and place a rangefinder to minimize the ranging error of the total station. Matters needing attention in the use of total station: (1) If the instrument has a long transportation distance, it must be inspected and calibrated before use, and it can be installed and calibrated directly according to the calibration method in the instruction manual of total station before use; (2) When the total station is used for trigonometric leveling control, it should be set up in the middle of two equidistant measuring points as far as possible to offset the influence of shafting error, so as to ensure the accuracy of the observation target and reduce the error; (3) When the total station is used for measurement, the position of the self-supporting station should be as far away as possible from the places where electromagnetic waves are emitted, such as substations, high-voltage lines, signal towers, etc., especially when the selected points are buried, so as to avoid electromagnetic interference with the instrument carrier, resulting in a large measurement distance error; (4) When the total station is used for advanced control measurement, the weather with good weather conditions and excellent visibility conditions should be selected as far as possible, and the observation time should be chosen to avoid the place with high temperature and large temperature difference between two points, and the results should be measured by the dry and wet temperature barometer, so as to correct the data during processing; (5) When using total station, try to avoid the flatness of the instrument caused by exposure. You should take an umbrella for musical instruments and wear a sunshade. In the process of use, always check whether the instrument is flat and fine-tuned, and set up a new orientation station when necessary to ensure its accuracy.
5 concluding remarks
According to the above research, we know that water conservancy project is the most important foundation in China's infrastructure construction. How to improve the accuracy level of hydraulic engineering survey is of great significance to the use of hydraulic engineering. Therefore, it is necessary to strictly control its technology in the survey, select the error analysis and precision control method of total station in water conservancy project survey, and seriously improve the quality of water conservancy project survey, so as to effectively ensure the quality of water conservancy project survey.
refer to
[1] Liu Yong, Wei Hanhua. Error analysis and precision control of total station in hydraulic engineering survey [J]. Enterprise Technology Development, 20 13( 19):55-56.
Von. Error analysis and precision control of total station in hydraulic engineering survey [J]. Beijing Agriculture, 2015 (24):133-134.
Pan Yongming. Error analysis and precision control of total station in hydraulic engineering survey [J]. Guangdong Science and Technology, 20 14(Z 1):89-90.
Hu yuejin. Error analysis and precision control of total station in hydraulic engineering survey [J]. Value Engineering, 20 15(02):57-58.
Graduation thesis of engineering survey research, Fan Wener's Problems and Countermeasures of Architectural Engineering Survey.
The process of measurement is well known, and it goes without saying that it is not a phased work, but runs through the whole construction project. In order to ensure that the construction of the building reaches the predetermined design goal, we usually test the specific construction in actual operation. This test is both an inspection and a test. After the completion of the construction project, surveying and mapping is still needed to provide data for subsequent construction and maintenance. Surveying can be said to be a bridge that connects the construction drawings with the actual construction of the bridge, and it is also a very important preparatory work, which has a very important impact on the quality of subsequent construction projects. There may be a misunderstanding that there is no need to test the projects that have been put into use because the whole construction project has been completed. In fact, even if it is put into production, it should be detected in time, which is more like a monitoring behavior, ensuring the safety and reliability of the construction process, which is very important. Therefore, the survey work runs through the whole construction work. The effectiveness and efficiency of measurement have a very important influence on the measurement results and the quality of the whole construction project to a great extent. Therefore, we should improve our understanding, realize the importance of measurement and do a good job in measurement. At present, there are also many problems in measurement, and only by solving these problems can we ensure the effectiveness of measurement.
1 Problems in architectural engineering survey
1. 1 The professional quality of employees is not high and there is a shortage of personnel.
At present, the problems existing in the survey work, the first of which is that the quality of employees is not high and there are fewer surveyors. This fundamentally caused some problems in the measurement work. In practice, many construction projects are based on cost considerations, and some inexperienced people in other positions are appointed to measure them. Because these people are unprofessional and have not received professional training, the measurement results can be imagined. In addition, there is a shortage of surveyors and even fewer professionals. This also increases the difficulty of accurate measurement to some extent.
1.2 outdated and insufficient measuring equipment.
At present, many construction companies do not have corresponding measuring equipment, and most of them are handled through temporary leasing. However, the measurement equipment of some enterprises is not updated in time and is very old, which has caused hidden dangers to the accuracy of measurement. If the enterprise equipment without corresponding equipment has some shortcomings, then it is necessary to find more sophisticated equipment, which will affect the progress of measurement. However, for enterprises with outdated equipment, the speed and accuracy of measurement are debatable because they have not kept pace with the times in time. So we should solve this problem from the equipment, so as not to cause more unnecessary effects.
1.3 Improper operation and maintenance of measuring instruments
The characteristics of measurement work determine that the equipment is a high-precision instrument, and the operators must undergo professional training. If the operator does not have the operation knowledge, there will be mistakes in the measurement process, even if it is only a small mistake, the measured results will be very different. Some precision instruments should be maintained and stored after use, otherwise the measurement effect will be affected. But in real life, this point is often ignored, and the operator does not maintain the instruments and equipment, which affects the accuracy. Of course, we must also pay attention to maintenance matters during use to ensure the accuracy of measured data.
Ignore the quality control of 1.4 measurement.
At this stage, most projects did not focus on the quality of measurement when they were completed and accepted, which was ignored to some extent. As a result, construction enterprises have not paid enough attention to the quality control of construction engineering survey, so that the existing measurement standards can not stand the test, and most of them can not meet the measurement standards and requirements, which seriously hinders the progress of construction engineering survey.
2. Problems and solutions in construction engineering survey.
2. 1 Strengthen the understanding of building construction survey
Measurement can be said to be an objective work, but we can't deny that it is also a subjective work. The method of measurement and the choice of measuring tools are all subjective consciousness and play a great role. But at present, people's backward subjective thoughts hinder the measurement work. Therefore, in order to ensure the smooth progress of measurement work, we must first strive for a scientific and correct understanding in thought. We should let the relevant workers abandon the wrong ideas and let people realize the importance and value of measurement. Only in this way can they fundamentally change their thinking and reverse the current measurement dilemma.
2.2 Increase investment in measuring instruments and strengthen their maintenance.
At present, technology has brought earth-shaking changes to our lives and brought good news to the measurement work. The progress of technology plays an important role in improving the accuracy of measurement. However, as mentioned above, many companies have outdated equipment and instruments due to cost considerations, so companies should keep up with the trend of the times and increase investment in measuring equipment and instruments. In order to meet the requirements of the rapid development of instruments and equipment and the measurement accuracy of building engineering. Of course, while increasing investment in instruments, we should also strengthen the maintenance of existing instruments. For example, in our daily measurement work, in order to avoid duplication, we should calibrate the instrument regularly. This seems troublesome, but it ensures the accuracy of measurement, avoids rework, and saves manpower, material resources and financial resources to some extent. When taking out the instrument, we should adhere to the principle of handling it with care. Attention should also be paid when the instrument is taken out and installed. If the instrument is installed on a tripod, tighten the screws to avoid breaking. The use of instruments should adhere to the principle of stability, and it is forbidden to treat instruments rudely, especially those with shock absorption function.
2.3 Strengthen the cultivation and training of relevant personnel.
With the acceleration of modernization and the increase of construction projects, the demand for the quality and quantity of surveying and mapping professionals is also expanding. In addition, with the development of measurement technology, various new equipment and technologies are constantly introduced, which puts forward higher requirements for the quality of our surveyors. At present, we should strengthen the training and cultivation of relevant personnel. This kind of training and training should improve the enterprise's understanding of measurement work and realize the importance of training. Of course, surveyors should also improve their understanding of self-study, exchange ideas and improve their professional quality. For the whole society, we should strengthen the investment in the training of surveyors. Only with the support of the state and the response of enterprises and individuals can the professional quality of surveying be improved in an all-round way.
3 Conclusion
With the rapid development of China's construction industry, there is no doubt about the requirements for the quality of construction projects, which requires us to keep pace with the times and constantly improve the current measurement methods and technologies, because the impact of measurement on the quality of buildings is very significant. So we need to know the problem, then analyze it and solve it. Only by solving this problem can we find a scientific solution and promote the development of the whole measurement work.
Engineering Survey Research Paper: Fan Wensan, Technical Analysis of Highway and Bridge Engineering Survey.
Located 2.3km upstream of Wuhan Yangtze River Bridge, Wuhan Yingwuzhou Yangtze River Bridge is the eighth Yangtze River Bridge in Wuhan, with a total length of 9.18km, in which the main bridge is 3.42km long and the deck is 38m wide. The main bridge has eight lanes in both directions, and the designed driving speed is 60 km/h. The Yingwuzhou Yangtze River Bridge in Wuhan is the first three-tower and four-span ground-anchored suspension bridge in China. The construction process has strong geometric nonlinearity and is very sensitive to wind speed, temperature and manufacturing error. Before the construction of catwalk, main cable and stiffening beam, the whole bridge should be measured. At the same time, in order to control the line shapes of main cables and strands, it is necessary to monitor the changes of span and pylon. Therefore, in order to ensure that the elevation and span of the bridge are consistent and the survey datum is unified, the bridge engineering requires high surveying and mapping technology, and the traditional surveying and mapping technology can no longer meet the requirements, while the application of modern surveying and mapping technology makes up for the deficiency, which provides technical support for the construction and realization of Wuhan Yingwuzhou Yangtze River Bridge.
Application of Surveying and Mapping Technology in 1 Planning and Design Stage
1. 1 Using VRS system to draw high-precision topographic map.
Using VRS system, that is, illusory reference station system, as long as the attributes and coordinates of breakpoints are collected, topographic maps can be drawn. Such a GNSS receiver can complete the work of multiple GNSS receivers, which not only reduces the measurement cost, but also improves the work efficiency. Moreover, compared with conventional surveying and mapping methods, the reliability and positioning accuracy of VRS system have also been greatly improved.
1.2 Establishment and application of integrated bridge survey and design system
The integrated system of bridge survey and design is an innovation of bridge survey and design under the condition of modern information technology: using GPS technology to obtain the three-dimensional coordinate space information of control points in aerial photography of highway bridges by unmanned aerial vehicles, and drawing topographic maps with the help of digital photogrammetry system; Using remote sensing technology to collect hydrogeological information along the bridge and draw it on the remote sensing map, the survey results can be obtained quickly, and the consumption is low, saving the survey cost; By transmitting the remote sensing information and terrain information collected in the field to CIS, the preliminary planning, scheme design and construction of bridge engineering can be carried out, and a series of work such as project establishment, evaluation, decision-making, bridge engineering survey and design also have strong information guarantee.
2 Application of Surveying and Mapping Technology in Construction Stage
2. 1 measurement of construction control network
The plane control network of a bridge is usually arranged in two levels, and the axis of the bridge is mainly controlled by the first level control network. According to the terrain conditions where the highway bridge is located and the river width that the bridge crosses, the layout of the first-class GPS plane control network is carried out according to the technical indicators of the first-class GPS control network. The first-level control network of highway bridges generally adopts GPS static relative positioning measurement, and then gets the plane positioning results through corresponding processing, which has the advantages of high precision, high efficiency and low cost. Because in the survey stage of highway bridges, the control points of design units can not meet the density requirements of construction lofting points in the construction process, and some inevitable points are destroyed, so it is necessary to control the survey network intensively. Using VRS dynamic survey, the three-dimensional coordinates of the measuring point can be obtained in the bridge engineering encryption control survey network. This method has been widely used in the survey of plane control network of small and medium-sized highway bridge construction, and achieved good results.
2.2 Construction survey of abutment and pier
It is one of the most important tasks in the bridge construction stage to accurately measure the center position of abutment and pier and their longitudinal and transverse axes. Direct measurement, electromagnetic wave ranging or intersection method can be used. In addition to the vertical and horizontal axes, it is necessary to locate the abutment and pier, set out the center line of abutment and pier, set out the erection position of main girder and set out the supporting cushion stone.
2.3 Installation construction survey
Before the erection of the main cable, the whole bridge should be surveyed to ensure that the elevation and each span meet the design requirements. The plane can be directly measured by total station coordinate method, and the elevation can be measured by total station trigonometric elevation method, and checked by level steel rule. In recent years, the emerging robot (locking) function has been more and more used to control the installation of highway bridges, and achieved good results.
2.4 emerging technologies in construction survey
With the development and progress of surveying and mapping technology, some more advanced and convenient technical means have been applied to the construction survey of highway bridges. VRS system can accurately set out points, lines, surfaces and slope lines, and cooperate with total station to give full play to their respective advantages. Super station instruments can be controlled by PTK technology where necessary. Using super station instruments to measure lofting can reduce the placement of total stations, which not only improves efficiency, but also improves accuracy. Because the super station instrument can be applied to all kinds of operations, it is time-saving, labor-saving and efficient, and this technology has been widely used in the whole field of architectural survey.
Application of measurement and mapping technology in operation stage
3. Application of1VRS system in highway bridge structure detection
In order to strengthen the quality management of bridges, in the process of highway bridge construction, quality supervision departments need to detect the axis, elevation, column position and bearing deviation of bridges. In traditional methods, supervision departments often use total station and other instruments to measure, which is greatly influenced by control points. With the development of GPS technology and network informatization, VRS technology has been widely used in bridge construction survey. At present, VRS system can set a fixed point in a construction bid section and take this point as a reference point. All highway bridge structures in this bid section can be detected by mobile stations, which greatly improves the overall detection accuracy.
3.2 Deformation Monitoring of Bridge Engineering
Because of the particularity of bridge engineering, it is necessary to study and carry out dynamic and static deformation monitoring of bridge in bridge deformation monitoring, which puts forward higher requirements for surveying and mapping automation technology and means. Compared with traditional leveling, VRS system is not only faster, shorter in cycle, but also more uniform in accuracy. The combination of VRS system and digital level can reduce the cost and time of highway bridge deformation monitoring by one third. The measuring robot can work automatically under the control of a computer by installing a full-automatic station instrument on a fixed station and cooperating with automatic detection software. It can not only collect, process and output three-dimensional data of deformation points, but also carry out remote online monitoring and management, which makes the detection of highway bridge engineering realize the latest and highest state of automation, intelligence and networking. In addition, three-dimensional laser scanning technology uses the principle of laser ranging to obtain the required target data, which can accurately describe the morphological characteristics and overall structure of the scanned object, generate a three-dimensional data model, make qualitative and quantitative analysis of highway bridges, and better detect the deformation in bridge operation and management.
4 conclusion
Surveying and mapping runs through the whole highway bridge project and plays a very important role in bridge construction. With the development of surveying and mapping technology and the application of new technology in highway bridge engineering, the operation method and measurement means of bridge engineering have undergone revolutionary changes. Modern surveying and mapping technologies such as PTK system, VRS system and automatic robot function will become the mainstream direction of highway and bridge engineering survey development in the future. They provide strong technical support for the modernization of highway and bridge engineering construction, promote the development of traditional highway and bridge engineering survey in the direction of digitalization, automation, networking and socialization, and enter a new era of surveying and mapping information.
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