First, the instrument selection

Suojia C32;

Suzhou Yiguang DT 102C front electronic theodolite;

Topcon GTS-332N total station;

The measuring instruments shall be in the charge of a special person. Measuring instruments should be inspected regularly, and daily maintenance, use and storage should be strengthened. Inspection records shall be kept. When using the instrument, the instrument shall not be separated from the instrument. Instruments should be placed in the instrument cabinet, which must be dry and dust-free. The instrument should be wiped and maintained frequently, and the usage should be recorded.

Second, the basic investigation plan and scheme

1. The engineering construction survey is based on the plane control points and elevation control points provided by Nanning Survey Institute and the positioning of Party A.. The site has been handed over to the pile point, and the specific location of the pile point is confirmed jointly. After the pile point was handed over, we carried out the putright and recheck of the pile point.

2. Understand the design intent, master the overall layout, engineering characteristics, construction deployment, progress, surrounding environment, site topography, positioning basis and positioning conditions, and make indoor calculations.

3. Establish the site plane control network and elevation control network, make control piles and obvious signs, properly protect them, and conduct recheck.

4. Measure the control line of each building and hand it over to the subcontractor (labor service team) in writing. The requirements for the control line are clearly marked, and the pile position is obvious. It is best to protect the pile point with concrete.

5. For the current site survey scheme: Due to the influence of site cross-construction, the site piles are easily damaged, so the total station can only be used to lead the piles to Jingsi Road, and then return to the working face for survey. The soil on site is greatly affected by sun and rain deformation, so the pile points on the working face should be checked and rechecked frequently. If the pile point is out of tolerance during inspection and recheck, the pile point should be re-measured.

III. Major investigation plans and schemes

1. elevation transfer

(1) First, according to the leveling points provided by Nanning Survey Institute, determine the elevation control points of the site with a level, and lay them on the stable buildings or structures around the construction site. During construction, use the elevation control points to control the elevation measurement of the underground part.

(2) Using the elevation control points, accurately measure the elevation measuring points on the side columns or external walls of buildings with a level gauge. In this direction, some points convenient for measurement are selected as the initial elevation measuring points of the layer above 0.000, and the relative elevation of the elevation measuring points should be unified as+0.500 m. ..

(3) The elevation putright of floors above+/-0.00 adopts 30m steel rule to putright upwards. During putright, use a steel ruler to putright vertically upward from the elevation putright point to the construction floor to determine the elevation point of the construction floor, and then set up a level gauge on the construction floor to putright two elevation points, one for rear view, one for checking and leveling, and measure each point as the construction basis. For the convenience of memory and construction, the elevation of each floor is determined to be +0.500M of the structural floor elevation of this construction floor, which will be used as the putright of all construction floors in the future.

2. Axis layout

(1) Establish the axis plane control network according to the actual situation, and select the representative vertical and horizontal lines to form the grid control network as the basis of the building axis.

(2) After the concrete is poured on the floor of the construction layer, the theodolite will be erected on the control points of each main axis (alternative axis) with a vertical instrument, and the corresponding axis will be aligned with the rear viewpoint, and the axis will be cast on the edge of the floor or the top of the column. In the same way, mark the mirror on the edge of the floor or the top of the column, and the positions of the front and rear mirror points are the same. If the error is within the allowable range, measure the midpoint. After the vertical and horizontal main axes are measured on the construction floor, assuming that the theodolite is on the floor, the corresponding points of the axes measured on the floor or the top of the column will be connected into a line by the positive and negative mirror method, and the chalk line will be played on the floor surface, which will be used as the baseline in turn, and other axes will be measured with steel ruler according to the dimensions marked in the design drawing.

(3) In the process of axis measurement, the main control line checks whether the line closure difference is within the allowable range, which means that the axis measurement is correct. If it exceeds the allowable error range, the reason must be found out and re-measured to ensure that the axis measurement accuracy meets the specification requirements.

Four, building settlement observation:

For deformation and settlement observation required by design drawings, settlement must be set as required.

Observation point, but in order to ensure quality control, we will set up temporary settlement observation points outside the building to increase the foot measurement.

Observation time requirements:

During the construction period; The first construction of the first floor structure will be carried out; After each floor is completed, the main structure construction is completed; Watch it again when you're done.

Five, measurement quality assurance measures

1. Purpose of measurement control

In order to effectively and accurately control the axis, elevation and verticality of the building in the construction process, and ensure that the verticality, elevation and geometric dimensions of the building meet the specifications and design requirements.

2. Requirements of measurement control

① All data provided in the measurement process must be true and accurate.

(2) The whole measurement process must record the data truthfully.

(3) The measurement error must be controlled within the following range:

Control axis: 1/7000 (> 20m), 3mm2 (≤ 20m).

Structural control line relative to axis: ≤ 3 ㎜.

Height: < 5mm2

Verticality: height ≤ 3 ㎜, overall height11000 and ≤ 20 ㎜.

3. Matters needing attention in elevation measurement

(1) When surveying the elevation, we should try our best to achieve the same length of sight distance before and after, so as to reduce the error.

(2) The steel ruler used must be inspected. When measuring the height difference, the ruler should be straight and use standard tension.

(3) The error value of the back viewpoint and checkpoint should be controlled within 2㎜, and the median should be adjusted, and the maximum error of each leveling point should not exceed 3㎜.

(4) When the height difference exceeds a whole steel rule, the second initial elevation baseline shall be accurately measured as the basis for upward putright to prevent error accumulation.

4. Matters needing attention in axis arrangement

(1) The main control axis point and the corresponding two points in each axis should be intervisibility, so as to reduce the putright error caused by excessive angle measurement caused by poor intervisibility.

(2) The inspection line of the main control line should be closed, or the error is within the allowable range, otherwise it should be rechecked to find out the reason.

(3) The measuring instruments used should be calibrated regularly. When installing the instrument, it must be strictly centered and kept level. Instrument testers and fixed personnel should contact each other through walkie-talkies.

5. The company will set up a full-time survey team to be responsible for the survey of this project. The surveyors shall make measurements under the arrangement of the heads of various disciplines on site. Before the measurement, the foreman of each major must make technical disclosure to the surveyors, put forward the measurement purpose and requirements, and recheck the measurement results of the surveyors. After the measurement is completed, the surveyor should explain the measurement results to the foreman and strictly control the elevation and axis.