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With the development of science and technology, the precision of equipment installation in industrial equipment installation engineering is getting higher and higher, especially for the equipment installation of long-span, long-distance and high-speed automatic production lines, such as the equipment installation of paper production lines, the allowable deviation of levelness and verticality is 0.3 mm
The accuracy of equipment installation depends on the embedded accuracy of anchor bolts, and the embedded accuracy of anchor bolts in a large range is determined by the accuracy of measuring and setting out. Therefore, mastering a complete set of high-precision measuring and setting-out technology is the basis to ensure the installation accuracy of equipment.
On the basis of several similar engineering practices, Suzhou Company has compiled this set of construction method of height measurement and setting out by Comrade Ma Jinhong. This construction method has been recognized and praised by foreign experts in many projects.
1, main technical features
1. 1 Using this method to establish the datum line network, the equality and verticality between datum lines can meet the requirements of high precision.
1.2 grid datum line runs through the whole factory building, which can be used by both the whole production line and a single device to ensure its installation accuracy with precision instruments.
1.3 grid baseline is used to control the embedded deviation of equipment anchor bolts, so as to reduce error propagation and ensure equipment installation accuracy.
1.4 makes use of the permanent preservation of datum points (lines) on the grid datum line, which is more convenient for equipment maintenance in the future production and operation process.
2. Scope of application
This method is suitable for the installation of automatic production line equipment with high installation accuracy, large span, long distance and fast operation speed. For example, the installation of paper machine production line, steel structure pipe rack installation in the factory area, etc.
3, construction preparation
Using the original vertical and horizontal control points of the factory building and with the help of precision measuring instruments (such as T2 theodolite, GTS-3 1 1 total station, etc.). ), set out the strip center line of the equipment in the factory building and the vertical and horizontal auxiliary center lines equal to and perpendicular to the center line, and set up control points on the vertical auxiliary center line, thus establishing the baseline grid.
4, process flow and operating characteristics
4. 1 process
Do control point datum → determine the bottom longitudinal and transverse center lines → determine the bottom longitudinal auxiliary center line → determine the starting point of each distance control point on the bottom longitudinal auxiliary center line → determine each distance control point on the bottom longitudinal auxiliary center line → measure the baseline grid of other floors (the method is the same as the bottom lofting method).
4.2 Key points of operation:
4.2. 1 Fabrication and Embedding of Control Point Reference Target
In order to preserve the control points for a long time, we can use stainless steel plate δ= 100 * 100mm to make a square datum point of 100mm, weld rivets on the lower part to cover the upper part, and connect the cover plate with the datum point with bolts to strengthen the protection of the datum point (see figure 1). The target plate can also be made of Ф ф= 25mm, L= 150mm copper bars, with the top turned over and tapped, the lower part processed into an I-shape, and the upper part covered with a plate (with threads), as shown in Figure 2.
After the benchmark target is made, each target will be accurately positioned and embedded when pouring on the bottom floor and floor. During the maintenance period, check and retest one by one on a regular basis to ensure the firmness and stability of the benchmark plate.
4.2.2 Measurement of longitudinal and transverse center lines of the bottom layer
During the implementation of this construction method, the precision requirements of the distance, verticality and straightness between two points are all less than 0.5 mm.
(1) Re-inspection of civil construction axis
Based on the civil axis, measure the vertical and horizontal center line of the bottom. The vertical and horizontal center line is the starting point of other reference lines, so it is very important to ensure the verticality of these two lines. Before measuring the longitudinal center line, we set up T2 theodolite at X2 and Y2 points, measure the intersection o of longitudinal and transverse axes of civil engineering, and mark this point on the benchmark with a punching machine. Then set up T2 theodolite at O point, check the verticality of the longitudinal and transverse axes of civil engineering by aligning the front and rear mirrors on both sides, and adjust its direction control points to make the verticality of the two axes of civil engineering meet its accuracy requirements.
(2) Measurement of longitudinal center line of bottom plate
The bottom longitudinal centerline is the starting point of other reference lines, so it is very important to ensure the accuracy of this line. T2 theodolite was set up at X 1 point and X2 point respectively, and vertical lines perpendicular to the longitudinal center line of civil engineering were drawn on the reference boards Os and Oe by the method of two-sided mirror. Then, according to the relative distance A between the civil longitudinal center line and the bottom longitudinal center line, GTS3 1 1 total station is set at points X 1 and X2 respectively, and the distance X65438 is measured. Re-check this distance with a steel ruler and a spring scale, and then mark these two points with a punch. The straight line OsOe passing through these two points is the longitudinal center line, as shown in Figure 3.
(3) Determination of horizontal centerline of bottom hole
According to the measurement method of the bottom longitudinal centerline, the vertical lines perpendicular to the civil transverse centerline are drawn on the reference targets T 10 and D 10 with T2 theodolite, and then the distances of Y 10 and Y2D 10 are measured with GTS300 total station according to the relative distance B between the civil transverse centerline and the bottom transverse centerline. Mark T 10 and D 10 points on the target board with a punching machine, and the straight line passing through T 10 and D 10 points is the bottom horizontal center line.
After measuring the longitudinal and transverse center lines at the bottom, use T2 theodolite or GTS3 1 1 total station to determine the intersection Oo of the longitudinal and transverse center lines according to the method of civil engineering axis review, and set up GTS31/total station or T2 theodolite at Oo point to detect the verticality of the longitudinal and transverse center lines and adjust them to vertical.
When calibrating O point and Oo point, we adopted the method of finding both sides of the mirror, which eliminated the deviation caused by the angle deviation of the instrument itself and ensured the accuracy of O point and Oo point. With this method, the linear error (less than 0.5 mm) relative to the vertical and horizontal center lines can be satisfied even if the manual point error is considered.
4.2.3 Angle of longitudinal auxiliary line at the bottom
When determining the bottom longitudinal auxiliary line, we divide it into the following two steps to ensure that it is parallel to the longitudinal center line.
Determination of vertical DSTS and DETE of (1) longitudinal centerline
There are two factors that affect the verticality error of drill pipe testing system and DETE pipeline relative to the longitudinal centerline. Taking DS as an example, the analysis is as follows:
(1. 1) Error δD caused by instrument angle deviation
We use T2 theodolite or GTS3 1 1 total station to make the angle deviation less than 5 ". In this method, │OsDs│ is 8m and has:
△d =(5÷206265)* 8000mm = 0. 19mm
(206265 is the conversion constant of angle radian) (1.2) Error caused by instrument deviation △ d'
(1.2) Error caused by instrument deviation △ d'
When using instruments to align points in construction, the distance between two points is generally more than 50m, and the error of manual operation can be guaranteed within 0.5mm, as follows:
△d =(8000 * 50000)*△dmax =(8000/50000)* 0.5mm = 0.08mm .
According to the law of error propagation, the influence of the above two terms on Ds is 0.2mm, which meets the accuracy requirement of 0.5 mm. ..
(2) Determination of longitudinal auxiliary direction points
When determining the longitudinal auxiliary direction point, we adopt the method of indirect measurement of small angle. The application of this method can make the distance error less than 0.5 mm Taking Ds point as an example, the analysis is as follows:
Set up a station about 5d away from the OsDs line (d=8m in this method), measure the distances d 1 and d2 with GTS-31total station, and measure the α angle with T2 theodolite. The cosine theorem D2 = D12+D22-D/kloc-0. Using the same method, we can determine three control points: De, Te and ts. In order to meet the parallelism requirements of longitudinal auxiliary line (DsDe, TsTe) and longitudinal center line OsOe. Error analysis:
According to the following figure, we assume that d 1=d2=b, then there is:
sinα= 2 sinα/2 cosα/2 = 2 * 4 * 40/ 16 16 = 0. 198
cosα= 1-2 sin 2α/2 = 1-2 * 16/ 16 16 = 0.980
According to cosine theorem: D2 = d12+d22-2d1d2cos α, the integral is obtained:
2d △ d = 2d1△ d1+2d2 △ d2-2d1△ d1cos α+2d1d2sinα (△α ρ) set.
△d=m, simplified as:
In the above formula, m = (d1-d2cos α) △ d1/d+(d1d2sin α (△ α/dρ):
Error of m- distance d, error of △d 1 distance d 1 (take 1mm).
△D2- error of distance d2 (take 1mm),
D—— Measuring distance (m)
ρ-conversion constant of angle radian (take 206265)
D1-as shown in the above figure (take 40.2m) D2-as shown in the above figure (take 40.2m).
△α-instrument angle deviation (take 2)
The above formula can be simplified as:
m=2b( 1-cosα)/d+2bsinα/dρ
= 2-40.2 * 0.02/8+2 *1616 * 0.198/8 * 206265 = 0.2 mm, which meets the accuracy requirement of 0.5 mm.
If it is convenient to use, you can also set some variables of the value of d and the value of b according to the calculation formula of m, and write a simple calculation program for computer calculation. From the results, we can choose the best value of b, and m tends to be very small, with the program attached.
10LETB= 1
20LETA= 1
30LETM=0.04b/d+0.396b2/206265d
40PRINT " b =B
50 Print "α"; A
60PRINT"m="M
70LETA=A+ 1
80-IFA & lt； 10 1THEN30
90LETD=D+ 1
100 ifd & lt； 2 1THEN20
1 10 ends
4.2.4 Determination of distance control points of bottom longitudinal auxiliary line
In 4.2.2, we have determined the Do and To points on the transverse centerline, which are the starting points of the distance control points on the longitudinal auxiliary line. According to the analysis in 4.2.3, the deviation of the longitudinal centerline can meet the accuracy requirement of 0.5 mm ..
4.2.5 Determination of distance control points of bottom longitudinal auxiliary line
After determining the starting point of each distance control point on the longitudinal auxiliary line, we can measure each distance control point by the average distance difference. In the application of this method, the following two items have great influence on its error.
The influence of (1) weighted constant error
Weighted constant error refers to the error caused by the inconsistency between the center of the instrument and the equivalent reflecting surface of the reflecting prism and the center of the distance mark to be measured. Its characteristic is that with the change of the measured distance, the influence of this error on the measured distance is constant and consistent in a certain period of time. Therefore, when applying this construction method, the influence of this error on the distance can be ignored.
(2) the influence of periodic error
Due to the influence of the internal circuit of the instrument, the measurement results change periodically with the distance. This change range is the periodic error, and the calculation formula is as follows:
ε=Acos[2πD/(λ/2)+ψo]
In the above formula: a- amplitude of periodic error d- distance.
λ-wavelength ψ of ranging light-initial phase
In order to eliminate this influence, we use the distance difference average ranging method, which can eliminate the influence of the above two errors, taking D 1 as an example:
Measure the distances Y 1Do and Y 1D 1 with GTS 31total station.
Then y1d1+y1y2 = DOD1+| y1do, that is to say ε | y 1d 1 | =
ε|DoD 1|+ε|Y 1Do|
Then ε DOD1= ε y1d1–ε y1do = acos [2π * y1d1(λ/2)+ψ 0]-
Use GTS3 1 1 total station to measure the distances Y2Do and Y2D 1.
Then y1d1+y1y2 = DOD1+(y1do+y1y2), that is:
ε (y1d1+y1y2) = ε' DOD1+ε (y1do+y1y2), then
ε' DOD 1 =ε(y 1d 1+y 1 y2)-ε(y 1Do+y 1 y2)
= Acos[2π*(y 1Do+y 1 y2)/(λ/2)+ψ0]
Compare (1) and (2) and take the average of the two results. You should do
εDoD 1+ε'DoD 1=0
Namely: acos [2π * y1d1(λ/2)+ψ 0]-acos [2π * y1do (λ/2)+9680] = acos [2π * (y/).
2πy 1d 1/(λ/2)= Acos[2π*(y 1d 1+y 1 y2；
/(λ/2)-π
2πy 1Do/(λ/2)= 2π(y 1Do+y 1 y2)/(λ/2)-π
Solution: Y 1Y2=λ/4.
Therefore, as long as Y 1Y2 is set to 1/4 of the ranging wavelength, the influence of period error and weighted constant error can be eliminated and the ranging accuracy can be improved. The wavelength of light wave can be obtained by consulting the relevant operating instructions according to different instruments. In this method, the wavelength of GTS3 1 1 total station is 20m.
4.3 other matters needing attention in the process of arrangement
The above layout method only controls the error theoretically. In practical work, we have also noticed other aspects that will have a certain impact on the measurement accuracy of control points, such as the alignment error of optical pointing device and meteorological factors. In the process of marking and marking, special care should also be taken. It is best to make the width of the marking line less than 0.2 mm and the diameter of the point less than 0.5 mm, so as to reduce the errors caused by human factors.
4.4 Determination of other factors grid baseline
In some projects, due to the requirements of equipment and workshop, the same baseline grid must be arranged on other floors. During this investigation, the investigation methods and steps are basically the same as those described in 4.2. The error is mainly caused by the verticality deviation between the longitudinal axis and the horizontal axis of the instrument itself. By taking the front mirror and the back mirror twice, some errors can be eliminated and the accuracy requirements can be guaranteed.
Through the above steps, we have established a complete datum grid line on each floor of the factory building, and used this datum line to embed anchor bolts in the later stage; Marking, drilling and tapping of foundation plate; In the levelness and verticality measurement of equipment, we can use T2 theodolite and GTS3 1 1 total station, with the help of some auxiliary tools (such as magnetic frame, ruler, etc. ), we can make all kinds of measurements and ensure the accuracy.
5. Main materials used
5.1δ =10mmd *1=100 *100mm stainless steel plate, or copper bar with d=25mm and l= 150mm.
5.2 Oxygen and acetylene
5.3d* 1\50*50mm angle steel
5.4I 14 I-beam and [10 channel steel
6, machinery and equipment
List of main construction machinery and equipment
8, quality requirements
In the process of compilation and implementation, this construction method conforms to the relevant provisions in Code for Engineering Survey (50026-3), and refers to the relevant instructions in GTS3 1 1 total station, T2 theodolite and NA2 level. At the same time, the accuracy of the grid baseline established by this method is very high, so before each construction, you should be familiar with the construction site and determine an overall construction plan. In the process of control, the survey engineer should be vigilant, carry out strict and detailed survey on each control point, and retest as required. At the same time, make construction records, personally supervise the auxiliary workers to embed each control target, and pay special attention to manual positioning to reduce human error to meet the accuracy requirements.
9. Benefit analysis
9. 1 social welfare
9. 1. 1 The use and exploration of baseline grid layout technology ensured the accuracy of baseline and the installation accuracy and quality of equipment, and won a high reputation for the company in the society.
9. 1.2 The use of high-precision baseline gridding measurement technology has solved the current situation that high-precision baseline cannot be set due to the lack of precision of the instrument itself, and it has also been recognized and affirmed by the construction unit and foreign installation experts.
9.2 Economic benefits
Using high-precision measuring and setting-out technology, the reference grid is established by itself. Compared with the entrusted investigation, its economic benefits are shown in Table 3.
See the analysis table for economic benefits:
In engineering, only this method can save100000 yuan even if the purchase cost of instruments is considered. Therefore, the economic benefits are considerable.
10, engineering example
This method was first applied to the installation project of Zixing Paper Co., Ltd. in 1995, and then it was also applied to many projects. See the engineering example list for details.
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