Building Settlement Monitoring Measures for Surat Metro Rail TBM Operation
摘要
A 36 km Metro Rail network is being constructed in the city of Surat, Gujarat, India, under Gujarat Metro Rail Corporation Limited, wherein a stretch of 7 km goes underground through heavily congested old city areas including 6 stations, with at least 200 old building structures in the vicinity and in danger of being affected for ground movement during launching shaft operations and TBM movement during underground tunneling and as well as Box pushing operations. On 01–03-2024, some ground settlement was recorded with minor cracks at the ground floor of Building ID No 401A, at Central Warehouse North Side Entry / Exit Box Pushing shaft area. The nearest corner of the building is roughly at a distance of 900 mm from the outer face of H–H-Pile to the edge of the column of the building. This building is located within the influence zone of the cut & cover shaft. Building Condition survey and Settlement analysis of the building was already done as per CIRIA report C580 and (Boscardin and Cording in J Geotech Engineer ASCE 115:1–21, 1989) paper. The building was of a ‘slight’ damage category during assessment. All the points of the building of approx. 100 m in length and 20 m in width were identified, and monitoring measures were taken for distortion and settlement of the building. Building settlement markers, 3D optical targets, crack meters, and inclinometers were installed, and 24X7 monitoring was started. Apart from monitoring, immediate measures like straight and inclined cement grouting up to 2 m depth at almost every 5 m distance were done, props were installed, and water seepage, if any, was closely monitored. Cavity filling in between soldier piles and the building face was done from the top surface and the grouting operation was done. Rainwater precaution for the upcoming monsoon season was also suggested to be taken care of by the contractor.