Settlement is the gradual sinking of a foundation or building.。Settlement observation refers to the measurement and recording of the settlement of the foundation or building，To understand the trend and cause of settlement.。Settlement observation，It is widely used in engineering construction.。
Topcon DL501 electronic level
Layout of settlement control points and settlement observation points：
During settlement observation，Set settlement points at positions that can represent settlement characteristics.，Bury the bench mark outside the influence range of settlement，Use the bench mark to measure the elevation of the settlement observation point regularly，So that that settlement condition of the build can be known from the change of the elevation of each settlement observation point。Set up 4 reference points in stable places，The number is：S1,S2,S3,S4, At the corners of a building、Bury the monitoring point at the obvious position of the midpoint，12 settlement monitoring points are arranged this time.。
Distribution map of monitoring points and settlement points
In order to accurately reflect the settlement of buildings and structures under continuous loading，It is generally stipulated that the measurement error shall be less than 1% of the deformation value/10~1/20，Therefore, a precision level should be used for settlement observation.，The leveling rod shall also be a high-precision indium steel leveling rod that is less affected by environmental and temperature changes.，TopconDLMeasurement accuracy of 501 electronic level 0.2mm，And that performance is stable，Autofocus，It is very suitable for the settlement observation which requires high observation accuracy.。
TopconDLOperation process of 501 electronic level settlement observation：
According to the technical design of project settlement observation and《Code for Engineering Surveying》Use the relevant requirements inDLThe 501 electronic level observes the datum point and the settlement point respectively.。In this paper, three closed loops are continuously observed according to the requirement of first order leveling accuracy for four datum points.,The closure error is±1.0√n mm,nIs the number of closed loop stations。When the accuracy is within the required range，Take the average value as the elevation starting value of settlement point deformation observation.。After the settlement point is set,The first observation can be made.，As the reference datum for the initial measured value of settlement observation。
Odd stations were used in the observation“Back, front, back and forth”，Even stations“Back and forth”The order of observation。Each observation starts from the reference pointS1 Let's go，Passing through all settlement observation points，And then close to S1，Form a closed loop ，When multiple buildings are observed at the same time, they can also be divided into multiple closed rings for observation.，But that star point must be the same。
Data processing：
After each observation，Utilize raw dataDL-The built-in adjustment program of 501 calculates the elevation of each settlement observation point.，Open a file with a spreadsheet，And collate the data.，Calculate the settlement of the current period and the cumulative settlement between each settlement point。
Or input the original data to the adjustment software of Tuojia Leveling Assistant for adjustment，Calculate the current settlement and cumulative settlement of each point according to the elevation of each settlement point calculated by adjustment.。
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The settlement shall be measured regularly according to the cycle requirements from the starting and ending date to the ending date of the project.，Record the change of settlement。
*Note：Tuojia level assistant，It can directly support the data format of Topcon level.，Output the adjustment report and automatically generate the current variation.、Cumulative change、Table of comparison results of change rate。
