How to control the network displacement of the deformation measurement point?

In the engineering survey code (GB50026-2007), the accuracy of building foundation pit deformation monitoring should not be less than the third class, and the error in the point position of the third class deformation observation point is, the second class is, the first class is, and the upper value of "1 divided by 2 under the root number" is taken in a specific direction as the limit. Yours is the second-class error in the height difference of the adjacent deformation monitoring point. Please take a closer look at the specification to see if it can meet such an observation accuracy In addition, if the distribution points are distributed, there are at least 3 datum points in the specification, and the working base point must have a forced centering device.

If you have any questions about the adjustment m= under the root number ( x square + y squared) you can contact you again together** Good luck!

The deformation observation and control network is the control basis for various deformation observations, which mainly includes the vertical displacement observation and control network (referred to as the elevation control network) and the horizontal displacement observation and control network (referred to as the plane control network), and the three-dimensional control network can also be established if necessary. The deformation observation and control network generally adopts the form of an absolute net (that is, all the control points are outside the deformation zone). When the building is located in an unstable area (such as expansive soil, landslide, etc.), the form of a relative net (i.e., the control points are all within the deformation zone) should be adopted.

In the absolute network, the deformation observation control points are generally divided into datum points and working base points. The reference point is the basis for checking the stability of the working base point, which is usually buried on a relatively stable bedrock or outside the deformation influence range, and is preserved for a long time as much as possible to make it stable and immobile. Since the datum point is generally set far away from the upward observation point of the deformed building, the working base point should also be set around the building to establish the connection between the datum point and the deformation observation point.

The level determined according to the accuracy required for deformation observation, that is, the level of the control network. In order to ensure the accuracy of deformation observation, the retest period of the control network should be determined according to the observation purpose and the stability of the point, and the retest should be remeasured once a year under normal circumstances. For the control points in the key monitoring areas, the retest period can be shortened as needed.

If there is any doubt about the deformation observation results, the control points should be checked and verified at any time.

The measurement points are encrypted for easy comparison and observation of the amount of change and the change trend.

In the past, it was good, but now it is deformed, and it is right to take the lead in mobilizing people to cross the bridge to raise funds to build it.

I don't know why.

In the engineering survey code (GB50026-2007), the accuracy of building foundation pit deformation monitoring should not be less than the third class, and the error in the point position of the third class deformation observation point is, the second class is, the first class is, and the upper value of "1 divided by 2 under the root number" is taken in a specific direction as the limit. Yours is the second-class error in the height difference of the adjacent deformation monitoring point. Please take a closer look at the specification to see if it can meet such an observation accuracy In addition, if the distribution points are distributed, there are at least 3 datum points in the specification, and the working base point must have a forced centering device.

If you have any questions about the adjustment m= under the root number ( x square + y squared) you can contact you again together** Good luck!

Foundation pit displacement measurement, make a point on the left and right sides of the unified mileage of the foundation pit, and measure the actual distance between 2 points every day!! Comparing whether the difference has changed or not is a displacement measurement.

Yes, the monitoring point is generally set on the edge of the foundation pit or on the crown beam.

Horizontal displacement and settlement can be measured.

Monitoring points are divided into three categories, datum points, working base points, and working points.

The datum point should be set outside the radius of influence of the deformation.

The working base point is set at the edge of the pit for easy use (each use must be checked for deformation) The working point is located at the main deformation point for detecting deformation.

1. Elevation datum points should be set for building settlement observation;

2. Plane datum points should be set for building displacement and special deformation observation, and elevation datum points should be set if necessary;

3. When the reference point is far away from the measured building, resulting in inconvenient deformation measurement operation, it is advisable to set the working base point.

In the construction process, this problem is often encountered, in my experience, there is a problem in the position of the initial selection point, in the main early completion of the control point must be checked when the position, if it is in the backfill of the place to do the point, then there will be a displacement, which should be regularly reviewed these control points, to see the size of the displacement, if the displacement is too large more than 1cm, the early opening and hiding to re-measure the point. Don't use the previous coordinate data anymore, otherwise the back land hall will be very serious.

If the displacement is too large and exceeds 1 cm, the point should be re-measured. Don't use the previous coordinate data anymore, otherwise the consequences will be serious. Reset the new coordinates.

Total station Yuyin, that is, electronic total station, is a high-tech measuring instrument integrating light, machine and electricity, and is a surveying and mapping instrument system integrating horizontal angle, vertical angle, distance (oblique distance, flat distance) and height difference measurement function. Because it can complete all the measurement work on the station if the instrument is destroyed at one time, it is called a total station. It is widely used in the field of precision engineering measurement or deformation monitoring such as large-scale above-ground buildings and underground tunnel construction.

According to the survey specifications, the Institute of Surveying and Mapping should ensure that it is reviewed every 3 months and report the results of the review of the control points to you, because he is obliged to provide the money after receiving money, if you find that the control point is offset, you should immediately report to the supervisor and the owner, and they will ask the Institute of Surveying and Mapping to provide the coordinates again.

In this case, you should put the secondary control point yourself, that is, according to the control point provided by the Institute of Surveying and Mapping, the review of this point should be at least once a month, and the deviation should be reported to the supervisor for immediate adjustment.

To be cautious, let's re-test the control point!

Remeasure the coordinates of the control point.

Deformation monitoring points are generally divided into three types: basic points, working base points and deformation measurement observation points.

1.Datum point.

The datum point is the datum for the deformation measurement and should be selected in a stable and reliable location outside the deformation affected area. Each project should have at least 3 datum points. For large-scale engineering projects, the horizontal displacement datum point should be the observation pier, and the vertical displacement datum point should be bimetallic or steel pipe standard.

2.Working base point.

The working base point should be stable during the deformation measurement of one cycle, and it can be selected in a more stable and convenient position. The observation pier should be used for the horizontal displacement monitoring work base point set up in the construction area of the large-scale project, and the steel pipe standard can be used for the vertical displacement monitoring work base point. For small projects with good visibility conditions, the deformation observation point can be directly measured at the reference point without setting up a working base point.

3.Deformation observations.

The deformation observation point is a measurement point that can reflect the deformation characteristics of the foundation, foundation, site and superstructure of the deformed body, also known as the deformation point.

1. External deformation observation refers to the changes in the external shape and spatial position of the deformed body, such as inclination, cracks, vertical and horizontal displacement, etc., so deformation observation can be divided into vertical displacement observation (often referred to as settlement observation), horizontal displacement observation (often referred to as displacement observation), oblique observation and crack observation;

Deflection (linear displacement perpendicular to the axis caused by deflection of the foundation, superstructure or components of the building under the action of bending moment), wind vibration observation (observation of deformation caused by strong wind), sunshine observation (observation of deformation caused by uneven heating by sunlight) and foundation pit rebound observation (observation of the phenomenon of uplift of the bottom soil of the pit due to the self-weight of the unloaded soil during foundation pit excavation), etc.

2. The observation of internal deformation refers to the changes in the internal stress, temperature, water level, seepage, and seepage pressure of the deformed body. In general, the surveyor is mainly responsible for the observation of external deformation, while the observation of internal deformation is generally carried out by other relevant personnel.

Compared with conventional measurement, one of the significant features of deformation observation is that the measurement accuracy is required to be higher, and the general ones should reach the millimeter level, and the important ones that are more sensitive to deformation should be even higher. Therefore, deformation observation is mostly a precision measurement.

According to the building settlement observation, the elevation datum point should be set;

II. Plane datum points should be set for the observation of building displacement, and elevation datum points should be set if necessary;

3. The reference point is far away from the measured building, which makes the deformation measurement operation cheap, and sets the working base.