Click on “construction survey” to pay attention to us
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Oh, just a year ago, during the RW project, we had no intention of opening the official account
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Thanks to the support from the majority of friends, we have been able to persist
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Now, the RW project is almost over
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RW Expressway Lot 9 is located in Dingxing County, Baoding City, Hebei Province
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The length of the lot is 8.3km, and the length of the bridge is 8km
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The rest are subgrade and a box culvert
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The main structure of the bridge is 24m, 30m and 40m prefabricated small box girder bridge
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The project belongs to several vertical and horizontal projects in xiong’an new area, with high attention and high schedule requirements
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During the construction period, there are two spring festival, epidemic situation and winter construction, and the real effective construction time is less than one year
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Project features: fast, fast, fast, the construction speed is very fast, measurement difficulties: with a group of young men who just graduated, how to let them in accordance with my established method in the implementation of the site without discount, to ensure that I can sit in the office every day and the site is orderly busy and error free; measurement objectives: no error in the field measurement, no delay in the progress of the site; management measures: control points can be adjusted Now the project has been basically completed (only the bridge guardrail is left), which is relatively smooth
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In the early stage, so many scattered summaries have been written piecemeal
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Here is a summary
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1
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Pile handing over: the on-site pile handing over work is carried out by the supervision engineer and the preparation office
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Because it is a line project, only on-site pile handing over is carried out, but no in-house pile handing over is carried out
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The on-site pile handing over only requires the supervisor to take two or three points, and we are also lazy to follow, because we found most of the points ahead of time and let them go to the next bid section for pile handing over
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We said that we should find the remaining points ourselves, he said Of course, they are very happy
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When chatting with the supervisor a few months later, he said that he knew at that time that you didn’t have to worry about the 9-lot measurement, because you all found the control points ahead of time, so you can be assured of doing things
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Therefore, the whole project construction process supervision has been very supportive of our survey work, which is really rare
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The reason for finding the points in advance is that the control points and results have been given in the design drawing, and then the points in the bid section have been found in advance by using Ovi map
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Therefore, in my opinion, pile delivery is the first contact between the project surveyors and the supervision, design or construction units
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The rigorous and professional work you show is very important for the smooth and effective development of the later survey work
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2
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Due to the flat terrain in the north and the simple bridge project, there are not many temporary works in the preliminary survey, mainly including the following works
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(1) Measure the height of the high-voltage line along the line
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There are several high-voltage towers across the line, which should be 110kV
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The site requirement is to measure the minimum height of the line
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The measurement method is relatively simple
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At that time, a Leica TM50 total station was brought into the site
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During the measurement, the total station was set up at about 100m from the vertical direction of the line
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One point was measured on the left and right sides of the line directly below the line (the side line of the line has been set out), and the elevation of the prism pole was measured at the lower point
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The height of the instrument was adjusted by input, so that the elevation of the instrument display interface was 1.3m, That is, at this time, the ground elevation is 0, the horizontal angle of the instrument is set to 0 ° 00 ′ 00 ″, the telescope of the instrument rotates upward until the horizontal wire of the instrument aims at the wire, and the horizontal angle of the instrument is checked and adjusted to 0 ° to read the instrument elevation directly
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At this time, the elevation displayed by the instrument is the elevation of the wire
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Now almost all total stations have this function (I don’t know if it is called overhanging height measurement), but the principle is the same as the angle eccentricity of eccentricity measurement
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That is to say, by measuring the horizontal distance of the ground point with the same distance from the wire, the height difference between the two points is calculated by the vertical angle difference between the two points, which is the same as the coordinate angle eccentricity in coordinate measurement
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The technical exchange group “construction survey group 2” established by Lao Ma last year is not full
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Welcome to join
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After this article, there is no plan to build another group
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(those who have entered the construction survey group and the monitoring group are not allowed to enter, and the three groups are about to merge.) Leica instruments sometimes rotate upward after measuring the prism point, and its elevation display does not move, because the instruments are not set properly
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If not, you can record the distance of the measuring prism, the vertical angle and the vertical angle of the wire to calculate, which is the same
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It should be noted that the position of the instrument should be 90 ° to the direction of the wire, so that the vertical angle of the wire will be more accurate
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(2) Site construction lofting includes site construction and temporary survey, mainly including topographic mapping, access road lofting, temporary land lofting, project department site and station construction lofting
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The mapping of topographic map is mainly reflected in the mapping of the scope of temporary land use
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The on-site survey mainly adopts RTK survey and hand drawn sketch for temporary mapping
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Because there is no very complex terrain on the site, it is mainly to investigate the number of graves and the direction of power poles, which is relatively simple
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The mapping adopts CASS7.1
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Station measurement takes up a lot of work in the preliminary work, although it is simple, but the workload is very large
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In the actual work, at least one surveyor is deployed to measure on site every day
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The drawings delivered by the technology department are all drawn in mm in CAD, such as the project department, mixing station, etc
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only after the surveyors convert to the measurement scale and put it into the line coordinate system, can the lofting work be carried out with the construction coordinate system
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There is no skill in daily lofting
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In the lofting of mixing station, it is necessary to observe the settlement of the tank
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In this project, digital level and ordinary black and red ruler are used for the observation, and everyone is required to measure a group of data
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The purpose of this is to make the staff familiar with the observation and calculation of leveling in advance
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The result is not ideal, and only one person’s measured data is correct
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In order to show the settlement deformation of the tank foundation more intuitively, the delivered results are presented to other personnel in the form of data sheet and deformation curve, and good results are obtained
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This is more intuitive than boring data, and other people don’t care about your benchmark, ruler readings and other process data
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In the temporary construction lofting, the lofting of the reinforced shed foundation in the precast beam field requires high accuracy
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The site construction personnel communicated with me in advance and required the accuracy to be within 5mm
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This is because the construction director has a little experience in the previous project
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This lofting is introduced in detail in this article: the inspection of the conventional coordinate lofting method with the error within 5mm and the pile delivery control In order to complete the retest of the control network before the formal drilling of the pile foundation, the retest work should be prepared after the pile is handed over
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It is difficult to retest for the first time, mainly due to the shortage of manpower and the need to ensure the daily temporary measurement while measuring the control network
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Therefore, there is not enough time and manpower to encrypt the whole line
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This requires that the retest of the control network must be fast, reliable, and able to encrypt some points to meet the requirements of the pile foundation construction period
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Only when these three conditions are met, the retest is meaningful, not for the sake of retest
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The main purpose of the first retest is to check the reliability of the pile delivery points, and carry out joint measurement with the bid sections on both sides, and then encrypt part of the points internally
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Therefore, all the encryption points choose the way of drilling holes and burying nails on the cement road, which is fast and does not need to wait for the concrete to dry
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The GNSS static network is the most important way to effectively connect the adjacent bid sections and ensure the overall accuracy of the plane coordinates
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The key is that it was extremely difficult compared with corn at that time, and only the static network can be used.
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