The in-situ monitoring sensor BWM460, which monitors the horizontal displacement of the soil, is a sensor developed by BEWIS SENSING.
With the rapid development of urbanization in China, more and more underground space has been developed and utilized, and the depth of foundation pit excavation is getting deeper and deeper. This makes the safety of foundation pit engineering highly valued. In actual work, obtaining real and effective foundation pit monitoring data can effectively reduce construction accidents and ensure construction safety and progress.
At the same time, with the continuous increase of foundation pit projects and the continuous improvement of on-site measurement data requirements, the inclinometer sensor plays an increasingly important role in foundation pit monitoring. In the foundation pit monitoring, the safety of the envelope structure is very important. The slope monitoring can ensure the safety and control of the foundation pit retaining structure.
From the analysis of a large number of foundation pit engineering accidents, it can be concluded that any accident of a foundation pit project is directly related to poor monitoring, inaccuracy and inconsistency. Foundation pit engineering monitoring is an important means to verify the correctness of the design plan, and it is also a necessary measure to promptly guide the correct construction and avoid accidents.
The project of foundation pit deformation monitoring includes surrounding buildings, land and bottom around the foundation pit, groundwater conditions, construction conditions, surrounding natural environment, maintenance structure and underground facilities, etc., and the key monitoring needs are the deformation of the bottom line of the foundation pit. The situation, the foundation pit and the settlement of the surrounding buildings, the stability of the surrounding maintenance structure, etc. In the actual monitoring process, because different engineering geological conditions are different and the content of key monitoring needs to be different, it is necessary for monitoring personnel to grasp the monitoring focus and ensure the safety of the foundation pit construction.
The inclinometer is an in-situ monitoring sensor that monitors the horizontal displacement of the soil and can be used to measure the horizontal displacement of soils at various depths. The BWM460 uses the latest MEMS technology and digital output cost-effective dual-axis inclinometer with a measuring range of ±60°, the highest precision of 0.005°, and an operating temperature of -40°C to +85°C.
The product uses a high-precision MEMS accelerometer and a high-resolution differential digital-to-analog converter with built-in automatic compensation and filtering algorithms to minimize errors caused by environmental changes. Converting the change of static gravitational field into dip angle change, directly outputting the horizontal dip angle value through serial communication, the base pit with this product as the core, high long-term stability, small temperature drift, simple use, strong resistance to external interference, is the basis The choice for pit deformation monitoring.
For the location of the foundation pit, sufficient precipitation should be carried out before the formal excavation, but the precipitation at the foundation pit will cause the groundwater in the surrounding soil to collect into the foundation pit. The groundwater flow will cause the instability of the land, and then induce the collapse of the soil. The emergence of this, in order to pay attention to the observation of groundwater in the process of precipitation. When burying the water level observation tube, the hydrogeological data of the project site should be carefully studied. For places with high water permeability and large water volume, the observation tube should be buried along the outer edge of the foundation pit every 25 m.
In the process of monitoring the deformation of the foundation pit, it is necessary to clarify the role and significance of the foundation pit monitoring. According to the monitoring content, the arrangement of the monitoring points and the burying of the equipment shall be carried out to determine the appropriate monitoring frequency, pay attention to the inspection during the monitoring of the foundation pit deformation, and determine the foundation pit. Deformation monitors reasonable alarm values, reduces the instability of deformation monitoring, and ensures the accuracy of foundation pit monitoring to ensure the safety of foundation pit construction.