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GB/T 12898-2009 English PDF (GBT12898-2009)

GB/T 12898-2009 English PDF (GBT12898-2009)

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GB/T 12898-2009: Specification for the third and fourth order leveling

This standard specifies the principles for the establishment of the third and fourth order leveling network, leveling methods, precision indicators and technical requirements. This standard applies to the deployment of the third and fourth order leveling network.
GB/T 12898-2009
GB
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 07.040
A 76
Replacing GB 12898-1991
Specifications for the third and fourth order leveling
ISSUED ON. MAY 06, 2009
IMPLEMENTED ON. OCTOBER 01, 2009
Issued by. General Administration of Quality Supervision, Inspection and Quarantine;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 4
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 6
4 Leveling network ... 7
4.1 Elevation system and elevation reference ... 7
4.2 Measurement accuracy ... 7
4.3 Layout principles ... 8
4.4 Benchmark layout density ... 8
4.5 Line naming and benchmarking numbering ... 9
4.6 Connection of new line and surveyed line ... 9
4.7 Technical design of leveling network ... 10
5 Point selection and stone burial ... 10
5.1 Point selection ... 10
5.2 Stone burial... 11
6 Technical requirements of instrument ... 13
6.1 Selection of instruments ... 13
6.2 Instrument calibration ... 14
6.3 Instrument technical indicators ... 15
7 Leveling observation ... 16
7.1 Observation methods... 16
7.2 Survey station setting requirements ... 17
7.3 Observation sequences and methods on survey stations ... 17
7.4 Interval and detection ... 19
7.5 Survey station observation tolerance, digits of reading, and settings ... 20 7.6 Matters to follow during observation ... 22
7.7 Observation of nodes... 23
7.8 Detection made in connect leveling or adjoining leveling of new and old lines ... 23
7.9 Round-trip observation height difference discrepancy and loop closure error tolerance ... 23
7.10 Repeated leveling and selection of leveling results ... 24
8 Cross-river leveling ... 25
8.1 Scope of application ... 25
8.2 Provisions for leveling methods and tolerances ... 26
8.3 Cross-river site selection and layout ... 26
8.4 Cross-river leveling observation requirements ... 27
8.5 Direct rule reading method ... 28
8.6 Leveling on ice ... 29
9 Electromagnetic distance measurement height traversing ... 30
9.1 Scope of application ... 30
9.2 Observation methods... 30
9.3 Height difference calculation ... 31
9.4 Measurement tolerance ... 33
10 Records, arrangements, and calculations of field achievements ... 33 10.1 Recording methods and requirements ... 33
10.2 Field calculation ... 34
10.3 Inspection and acceptance of field achievements and submission ... 36 Appendix A (Normative) Drawing format of selected stone burial data and mark stone fabrication and burial descriptions ... 38
Appendix B (Normative) Instrument inspection method ... 58
Appendix C (Normative) Cross-river leveling vane production and observation records ... 83
Appendix D (Normative) Observing handbook format and height difference
table compilation ... 86
Specifications for the third and fourth order leveling
1 Scope
This standard specifies the principles for the establishment of the third and fourth order leveling network, leveling methods, precision indicators and technical requirements.
This standard applies to the deployment of the third and fourth order leveling network.
2 Normative references
The provisions in following documents become the provisions of this Standard through reference in this Standard. For the dated references, the subsequent amendments (excluding corrections) or revisions do not apply to this Standard; however, parties who reach an agreement based on this Standard are
encouraged to study if the latest versions of these documents are applicable. For undated references, the latest edition of the referenced document applies. GB/T 3161 Optical Theodolite
GB/T 10156 level
GB/T 12897-2006 Specifications for the first and second order leveling
GB/T 16818 Specifications for short to medium ranges electro-optical
distance measurements
CH/T 1001 General rules for technical summaries of surveying and mapping CH 1002 Specifications for inspection and acceptance of surveying and
mapping products
CH 1003 Standard for quality assessment of surveying and mapping
products
CH/T 1004 General rules for technical design of surveying and mapping
CH/T 2004 The general rules of the electronic data recording for field
surveying
CH/T 2006 The electronic data recording rules for leveling
JJG 8 Specifications for leveling rule verification
JJG 425 Verification regulation of levels
JJG 414 Verification regulation of optical theodolite
JJG 703 Verification regulation of electro-optical distance meter (EDM
instruments)
JJF 1118 Calibration specification for global positioning system (GPS)
receiver
3 Terms and definitions
The following terms and definitions apply to this standard.
3.1
Node
The benchmark in the leveling network that connects at least three leveling lines.
3.2
Leveling line
Leveling line between two adjacent nodes in the same order leveling network. 3.3
Section
Leveling line between two adjacent basic benchmarks in a leveling line. 3.4
Leveling section
Leveling line between two adjacent benchmarks.
3.5
Connect leveling
The observation of including a benchmark or other elevation point in a
leveling line.
3.6
stone every 4 km ~ 8 km; in densely populated and economically developed areas, it can be shortened to 2 km ~ 4 km; in desert areas, the leveling branch lines can be increased to about 10 km. The mark stone may not be buried when the branch line length is within 15 km.
4.5 Line naming and benchmarking numbering
4.5.1 The leveling line uses the abbreviation of the starting and ending geographical names as the line name, the order of starting and ending
geographical names shall be from west to east, and from north to south. As for the ring name, it is composed of the geographical name of the largest place in the ring followed by the letter ?€?ring?€?. The grade of the third and fourth order leveling lines are respectively represented by III and IV in front of the line name. 4.5.2 The benchmark on the line shall start from the starting benchmark of the line, the point is numbered in the sequence of 1, 2, 3..., the point number sequence along ring shall be clockwise, the points shall be numbered in the sequence of number 1, 2, 3...
4.5.3 Leveling branch line is named by the surveyed elevation point name followed by the letter ?€?branch?€?. The benchmark stone of the branch line is numbered in the sequence of number 1, 2, 3... along the direction from the starting benchmark to the surveyed elevation point.
4.5.4 When using the old benchmark, the old benchmark name and number
shall be used. If it is really necessary to renumber it, the new name shall be followed by a bracket to indicate the name of the benchmark where it was buried. 4.6 Connection of new line and surveyed line
4.6.1 The starting point and end point of the newly established leveling line shall be the benchmarks of the surveyed higher or equivalent order leveling line. 4.6.2 When the newly established third and fourth order leveling line is within 4 km away from each surveyed equivalent benchmark, it shall be subject to connect leveling or adjoining leveling. In case of adjoining leveling, it shall check the surveyed benchmarks in accordance with the provisions of clause 7.8. 4.6.3 For the adjoining leveling of the benchmarks on the surveyed line, it shall be performed in accordance with the requirements of the lower level accuracy of the newly surveyed line and the surveyed leveling line.
4.6.4 When the new line is coincident with the surveyed line, if the old mark stone complies with the requirements, it shall use the old mark stone as far as possible. If the old mark stone does not meet the requirements, it shall select A.6 of Appendix A. The protection wellbore wall shall not interfere with the survey of the lower mark.
b) For the leveling mark stones buried in institutions, schools, residential buildings, and cultivated land and water network areas, it shall build the protection well and add the protection cover in accordance with the
specifications in A.6 of Appendix A.
c) In open areas such as forests, grasslands, deserts, and Gobi, in addition to the construction of protective wells and protective cover as required, two or three bearing pickets may be set up nearby, or small targets may be constructed.
d) For mark stones buried in the mountains and forest areas, the bearing pickets can be installed on the roadside closest to the benchmark. Bearing pickets and targets can be made of wood, stone, concrete or metal
materials. The benchmark number and location direction are marked at
an eye-catching position by the use of red paint or embossing method.
Indicate the direction and distance of the laid topographic marker in the description of benchmark.
5.2.4 Control of key processes
At the site where the mark stone is buried, the following photographs shall be taken.
a) The photographs of the mark stone pit, which shall reflect the shape and size of the mark stone pit and foundation pits;
b) Photographs of mark stone placement, which shall reflect the shape and size of the mark stone;
c) The photographs of mark stone after trimming, which shall reflect whether mark stone trimming is normalized;
d) The prospective photographs of the burial location of the mark stone, which shall be able to reflect the features and geomorphological
landscape of the burial location of the mark stone.
5.2.5 Land occupation and hosting of mark stones
5.2.5.1 The land occupied by the mark stone shall obtain the consent of the land management department and the land user organization or individual. 5.2.5.2 During the process of mark stone burial, the statutory duties and precautions for the protection of measurement marks shall be publicized to the local people and cadres. At the end of the mark stone burial, the relevant governmental departments at the local township or above shall go through the a) The black side of the rear view scale (basic division);
b) The black side of the front view scale (basic division);
c) The red face of the front view scale (auxiliary division);
d) The red face of the rear view scale (auxiliary division).
7.3.1.2 The leveling division sequence of the fourth order leveling scale for each survey station is.
a) The black face of the rear view scale (basic division);
b) The red face of the rear view scale (auxiliary division);
c) The black face of the front view scale (basic division);
d) The red face of the front view scale (auxiliary division).
7.3.1.3 The optical micrometer method is used for survey station observations. The operating procedure of a survey station is as follows (taking the third order leveling as an example).
a) First level the instrument (When the bubble-type level instrument
telescope rotates around the vertical axis, the separation of the image at both ends of the leveling bubble shall not exceed 1 cm. The circular bubble of the automatic leveling instrument shall be located at the center of the indicator ring);
b) Position the telescope on the black surface of the rear view scale, use the tilt screw to adjust the leveling bubble to center accurately, read the scale reading accurately in accordance with the stadia wire and central wire (for the fourth order observation, it may not read the reading of the upper and lower wires, but read the distance directly);
c) Rotate the telescope to aim the black face of the front view scale, and operate in accordance with item b);
d) Aim the red face of the front view scale and operate in accordance with item b).
e) Rotate the telescope to aim the red face of the rear view scale, and operate in accordance with item d).
When using a single-row Invar scale for observation, the single-row division is subject to two times aiming reading to substitute basic and auxiliary division reading.
7.3.2 Digital level observation
7.3.2.1 The aiming scale sequence of each survey station by the round-trip survey of the third order leveling is as follows.
a) Rear view scale;
b) Front view scale;
c) Front view scale;
d) Rear view scale.
7.3.2.2 The aiming scale sequence of each survey station by the round-trip survey of the fourth order leveling is as follows.
a) Rear view scale;
b) Rear view scale;
c) Front view scale;
d) Front view scale.
7.3.2.3 The operating procedure for a station is as follows (taking a third order leveling as an example).
a) First level the instrument (the telescope rotates around the vertical axis, and the circular bubble is always at the center of the index ring);
b) Align the telescope with the rear view scale, use the vertical wire to aim the center of the bar code, accurately make focusing until the bar code image is clear, press the measurement key;
c) After readings are displayed, rotate the telescope to the center of the front view bar code, accurately make focusing until the bar code image is clear, press the measurement key;
d) After readings are displayed, re-aim the front view scale, press the measurement key;
e) After the readings are displayed, rotate the telescope to the center of the rear view bar code. Accurately make focusing until the bar code image is clear, press the measurement key, to display the survey station results. After the survey station passes inspection, transfer the station.
7.4 Interval and detection
7.4.1 In case of interval of observations, it is best to end the observation at the benchmark. Otherwise, it shall select two fixed points which are stable and - Operate in accordance with the instruction manual of the instrument.
7.6 Matters to follow during observation
7.6.1 At 30 min before the observation, the instrument shall be placed in the shadow of the open air, so that the instrument tends to be in line with the outside temperature; when setting up the survey station, the umbrella shall be used to shield the sunlight; when moving the survey station, the instrument shall be covered. Before using a digital level, it shall also be warmed up, which is not less than 20 single leveling.
7.6.2 For a bubble type level, the leveling zero point of the tilt screw shall be measured and marked before the observation. The zero position shall be
adjusted at any time as the temperature changes. For the level of the automatic leveling instrument, it shall be strictly leveled before the observation. 7.6.3 When the tripod of the leveling instrument is to be placed on successive survey stations, the two feet shall be parallel to the direction of the leveling line, and the third foot shall be alternatively placed on the left and right sides of the line direction.
7.6.4 Except for the turning of the line, the three positions of the instrument and the front and rear view scales at each survey station shall approach a straight line.
7.6.5 The scale stake (platform) shall not be placed in a pit in order to increase the reading of the scale.
7.6.6 The number of survey stations for the direct observation and reversed observation for each leveling section shall be an even-number. When changing from direct observation to reversed observation, the places of the two scales shall be switched, and the instrument shall be reset.
7.6.7 When performing the third order and fourth order leveling in the areas of large height difference, it shall use the DS3 grade above instrument and scale to make leveling as far as possible.
7.6.8 When rotating the instrument?€?s tilt screw and micrometer drum, its final rotation direction shall be precession.
7.6.9 For digital leveling instruments, avoid the telescopes from direct aiming to the sun; try to avoid shielding of the line of sight; the shielding shall not exceed 20% of the intercept of the scale in the telescope; the instrument can only work within the temperature range specified by the factory; the measuring key cannot be activated until the vibration caused by the vibration source has disappeared. 7.3.2.1 The aiming scale sequence of each survey station by the round-trip survey of the third order leveling is as follows.
a) Rear view scale;
b) Front view scale;
c) Front view scale;
d) Rear view scale.
7.3.2.2 The aiming scale sequence of each survey station by the round-trip survey of the fourth order leveling is as follows.
a) Rear view scale;
b) Rear view scale;
c) Front view scale;
d) Front view scale.
7.3.2.3 The operating procedure for a station is as follows (taking a third order leveling as an example).
a) First level the instrument (the telescope rotates around the vertical axis, and the circular bubble is always at the center of the index ring);
b) Align the telescope with the rear view scale, use the vertical wire to aim the center of the bar code, accurately make focusing until the bar code image is clear, press the measurement key;
c) After readings are displayed, rotate the telescope to the center of the front view bar code, accurately make focusing until the bar code image is clear, press the measurement key;
d) After readings are displayed, re-aim the front view scale, press the measurement key;
e) After the readings are displayed, rotate the telescope to the center of the rear view bar code. Accurately make focusing until the bar code image is clear, press the measurement key, to display the survey station results. After the survey station passes inspection, transfer the station.
7.4 Interval and detection
7.4.1 In case of interval of observations, it is best to end the observation at the benchmark. Otherwise, it shall select two fixed points which are stable and 7.7 Observation of nodes
7.7.1 When observing to the nodes of the leveling network, it shall make detailed records of the adjoining leveling in the observation handbook, the node adjoining leveling is in accordance with A.3.
7.7.2 Nodes located in the ground deformation area shall be subject to adjoining leveling with the local deformation observation network.
7.7.3 Nodes located in areas with large deformation shall be subject to cooperative work by several observation groups to minimize the adjoining leveling time.
7.8 Detection made in connect leveling or adjoining leveling
of new and old lines
7.8.1 When the newly established leveling line is subject to connect leveling or adjoining leveling with the surveyed benchmark, if the observation time interval of this benchmark exceeds 3 months, it shall be detected.
7.8.2 When the third and fourth order leveling lines (or branch lines) are subject to connect leveling with the surveyed benchmarks, it shall detect a surveyed leveling section in single trip. If the results of the single-trip detection exceed limits, it shall detect the other single trip of this leveling section. If it still exceeds limit, it shall continue forwarding detection, to determine a stable and reliable surveyed point as the connect point. If the intersection point changes, it shall make repeated leveling of the relevant leveling section.
7.8.3 The detection of higher order leveling line shall be conducted in accordance with the order of the newly established line; the detection of lower order leveling line shall be conducted in accordance with the order of the original leveling line.
7.9 Round-trip observation heigh...

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