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GB/T 12898-2009 PDF in English


GB/T 12898-2009 (GB/T12898-2009, GBT 12898-2009, GBT12898-2009)
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GB 12898-1991EnglishRFQ ASK 11 days Specifications for the third and fourth order leveling Obsolete
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GB/T 12898-2009: PDF in English (GBT 12898-2009)

GB/T 12898-2009 GB NATIONAL STANDARD OF THE PEOPLE’S 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 & 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 height difference discrepancy and loop closure error tolerance 7.9.1 The round-trip observation height difference discrepancy, the tolerance of the difference between the loop closure error and the detected height difference shall not exceed the requirements of Table 9. meanwhile the discrepancy between its mean and the originally surveyed height difference of the other single-trip does not exceed tolerance, the mean of this same direction is taken as the height difference of this single trip. If it exceeds the above tolerance, the other single trip shall be subject to repeated leveling. b) In single-trip double-turn point observation, when the discrepancy between the height differences of the right and left lines of the leveling section exceeds tolerance, it may perform repeated leveling for a single- trip single line, and take the mean of it and one of the original survey result which complies with tolerance requirements; if both the results of the repeated leveling and the original leveling comply with tolerance requirements, take the mean of the three single line results. When both the results of the repeated leveling and the two single line results of the original leveling exceed limit, it shall analyze the causes and perform the repeated leveling for a single-trip single line. c) When the accident error square error MΔ per kilometer leveling which is calculated from the discrepancy of the round-trip height difference (or left- right line height difference) exceeds the limit, some of the leveling sections with large discrepancy values shall be subject to repeated leveling. d) When the loop closure error exceeds the limit, it shall perform repeated leveling against the leveling section of lower reliability (a large discrepancy in the height-difference of round-trip observation or that which is poor in observation conditions). When the annexed line closure error exceeds limit, it shall analyze the causes and re-survey the relevant leveling sections. In areas of large height difference, it should include the gravity anomaly correction. 8 Cross-river leveling 8.1 Scope of application When the leveling line spans rivers (or lakes, wide gullies, depressions, valleys, etc.) and the sight line length is within 200 m, general observation methods may be used, but the height of the instrument shall be changed once at the survey station to make two observations. The difference between the two height differences shall not exceed 7 mm, take the median of the two results. If the length of line of sight exceeds 200 m, the method described in this clause shall be used for observation in accordance with the length of sight and equipment and other conditions. It shall not be excessively inclined or swing. e) After completion of one observation, it shall suspend for 15 min ~ 20 min, then start the next observation. f) Before the start of cross-river observation, a round-trip leveling shall be conducted between the common leveling stones (or fixed points) on both sides of the river and the scale points, as a benchmark for detecting the change of the scale points. Before the start of the daily work, it shall perform one single-trip detection, the results shall comply with the detection tolerances as specified in 7.9. If it confirms that the scale point changes, it shall reinforce the scale point to perform the cross-river leveling observation again. 8.5 Direct rule reading method 8.5.1 Observation methods The observation method of each observation set is as follows. a) After leveling the leveling instrument at the center of the points I1 and b1 (or I2 and b2) and at the point in same distance from I1 and b1, use the same scale to determine the height difference I1b1 in accordance with the general operating procedure. b) Move the instrument to point I1. After leveling the instrument precisely, aim the near scale on the b1 point of the bank, read the basic & auxiliary division once based on central wire. c) Turn the instrument to aim the far scale on the I2 point of the opposite bank. After adjusting the focus, use the tape to fix the focusing screw, read the basic & auxiliary division twice, respectively, based on central wire. d) Immediately move the instrument to point I2 on the opposite bank, ensuring that the focusing screw is not touched. Meanwhile move the scale on point b1 to point I1. After leveling the instrument precisely, first aim the far scale at point I1 on the opposite side, take readings based on the reversed sequence of c), b), a) and the operating requirements. e) Move the instrument to between I2 and b2 and at equal distances. Measure the height difference hI2b2 between I2 and b2 in accordance with the normal operation method. The above a), b), and c) are for the first half observation, d) and e) are for the second half observation. as those for the corresponding order of leveling. 9 Electromagnetic distance measurement height traversing 9.1 Scope of application In the mountainous areas and swamps and water network areas where geodetic leveling is difficult, the fourth order leveling lines or branch line may be subject to leveling by electromagnetic distance measurement height traversing wires (hereinafter referred to as height traversing). 9.2 Observation methods 9.2.1 Before height traversing, it shall select the survey stations along the line. The length of sight line is generally not more than 700 m, the maximum length does not exceed 1 km, the vertical angle of line of sight shall not exceed 15’. The height of line of sight and the distance from the obstacle shall not be less than 1.5 m. 9.2.2 The height traversing may be arranged for the line that each aiming point is arranged with instrument for opposite direction observation (hereinafter referred to as establishing survey station at each point); it may also be arranged for the line that the instrument is placed at every other aiming point (hereinafter referred to as establishing survey station at every other point). In case of establishing survey station at every other point, it shall use the single-trip double-leveling method, that is, make two observations for each station by changing the height or location of instrument, the difference between the front and rear sight line length shall not exceed 100 m. 9.2.3 In case of distance measurement by electromagnetic distance meter, preparation of distance measurement, observation methods and operation requirements, meteorological element determination, record of results and repeated leveling selection, calculation of correction value of meteorology, additive constants, multiplicative constants, and the edge length reduction shall be in accordance with the corresponding provisions of GB/T 16818. 9.2.4 Technical requirements and observation tolerances for distance measurement are as follows. a) Observation of the slant distance and vertical angle shall be performed with clear imaging and stable signal; Appendix B (Normative) Instrument inspection method B.1 Visual inspection of scale B.1.1 Whether the scale has dents, cracks, bumps, scratches, paint stripping and so on. B.1.2 Whether the scale marking line is clear and whether there is any abnormal flaw. B.2 Calibration of circular level on leveling scale B.2.1 Place a leveling scale on a ruled peg approximately 50 m away from the leveling instrument so that the centerline (or edge) of the leveling scale coincides exactly with the vertical wire of the telescope. If the air bubble on the scal...... ......
 
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