优化生物倍增工艺提高除氮效率

监测基准网是沉降监测的参考基准，基准点是监测的基本控制，监测基准点的稳定性是重要前提。本文结合武汉地铁6号线下穿4号线隧道沉降监测工程，针对监测基准点布设困难及其稳定性和可靠性问题，采用平均间隙法和分块间隙法相结合，通过多期水准观测数据分析，提取了稳定可靠的监测基准点，保障了施工隧道的沉降监测。

Analysis on Stability of Relative Datum Network for Monitoring the Settlement of Overlapping Tunnels

The datum network is the reference of the settlement monitoring,the datum benchmarks are basic control, and its stability is the most important guarantee for the monitoring. Based on the settlement monitoring of overlapping tunnel section near the zhongjia village station of Line No. 6 and Line No. 4 of Wuhan Metro,this paper give a detail a-nalysis on the datum selection and the stability of the datum benchmarks. By using multi-times observations of leveling survey,the stable and reliable datum benchmarks are extracted by combing the average clearance inspection method and blocking clearance inspection method,which ensure the subsequent monitoring of the settlement in the construction.