Application Of Integrated Monitoring Technology In Foundation Pit Engineering The Study

At present,in the construction monitoring of foundation pits,many monitors find that the measured data exceeds the alarm value,and rarely analyze whether there is a hidden danger or a trend under the data,but directly report the alarm,which leads to the neglect of the real danger.Therefore,comprehensive research on deformation research and mechanics research for foundation pit engineering is to further reveal the safe operation of foundation pits,ensure the safe and stable operation of foundation pits,improve the reliability of the entire foundation pit engineering and enrich the theory of geotechnical disciplines.Both have important theoretical and practical significance.This paper relies on a foundation pit monitoring project in Guangdong Province,using numerical judgment,analogy method and comprehensive comparative analysis method for comprehensive research.(1)The maximum horizontal deformation of the foundation pit monitoring in the soft soil area is generally 50 mm,and the daily development control value is not allowed to exceed 3mm;the data curve is drawn according to the daily displacement monitoring results,and the inclination and depth of the supporting structure are A smooth curve of the bending moment,if the curve shows a significant inflection point,it also needs to be handled by an alarm.(2)Correct the calculation of the maximum displacement of the enclosure and the maximum settlement formula of the soil by the stability safety factor method:the stiffness and support spacing of the retaining structure,define the correction coefficient?_w;support stiffness and spacing,define the correction coefficient?_s;Buried depth,defining correction coefficient?_D;foundation pit width,defining correction coefficient?_B;supporting pre-axial force,defining correction coefficient?_P;soil modulus multiplier(the relationship between modulus and undrained shear strength,ie coefficient),the correction coefficient?_m is defined;for the support structure,the anchor(anchor cable)should take into account the influence of temperature,and define the correction coefficient?_t.(3)Multi-data comprehensive analysis There may be risk sources in the foundation pit:the measured value of the inclination of the foundation pit suddenly increases,usually in the symmetrical position of the foundation pit,and the corresponding supporting axial force is too large,and there is a possible risk source—the soil There is a horizontal or vertical over-excavation phenomenon;the cumulative value of soil settlement exceeds the standard,and the lateral displacement corresponding to the foundation pit does not match,which is much larger than the lateral displacement of the foundation pit,but the supporting axial force of the foundation pit does not change significantly,and there is a possible risk.The source-precipitation speed is improper;the rise of the support column far exceeds the warning value,but the displacement of the support is not obvious,and the increase of the support axial force tends to be gentle with time,there is a possible risk source—the precipitation is extremely insufficient;The measured value is abnormal,accompanied by the inconspicuous settlement of the soil,and the risk source is incorrect when the foundation pit sees water leakage.(4)Using the existing theoretical analysis to verify the safe operation of the foundation pit on the basis of the measured data,it is concluded that the single data can not reflect the overall safety status of the foundation pit,and must be analyzed by multiple data,multi-parameter and multi-angle.