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地下连续墙作为基坑围护结构起到支撑周围土层及防水的目的,接头处渗漏监测是检验嵌岩地下连续墙防渗质量的有效方法。结合南京地区采用“Ⅱ”型接头嵌岩地下连续墙的基坑实际工程,用20个监测孔对地下连续墙单元连接位置进行渗漏监测,结合接头处渗漏情况的现场监测数据,重点分析各监测孔的渗漏量大小、渗漏流速随深度的变化、渗透系数随深度的变化,并对“Ⅱ”型接头处做过与未做过高压旋喷钻孔灌注桩进行渗漏对比分析。监测结果表明:20个监测孔渗漏量均较小,其中按头部位做过高压旋喷钻孔灌桩处理的监测孔S4渗漏量最大,在深度8~25m范围内更易发生渗漏,该深度范围的渗漏流速及渗透系数也比其他深度的大,接头处做过高压旋喷钻孔灌注桩处理的监测孔S16~S20在深度35~55m范围也有上述现象;5个接头处未做过高压旋喷钻孔灌注桩处理的监测孔没有出现渗漏异常现象。
Diaphragm wall as a foundation pit retaining structure to support the surrounding soil and waterproof purposes, joint leakage monitoring is an effective method to test the anti-seepage quality of the diaphragm wall embedded in rock. Combined with the practical engineering of pit for embedding “Ⅱ” type joint diaphragm wall in Nanjing in Nanjing, 20 monitoring holes were used to monitor the connection position of diaphragm wall unit. Based on the site monitoring data of joint leakage, Focus on the analysis of the size of the monitoring hole leakage, leakage flow velocity changes with depth, permeability coefficient with the depth of the change, and the “Ⅱ” type joints done with and without high pressure rotary jet grouting bored pile Leakage comparison analysis. The monitoring results showed that the leakage of the 20 monitoring holes was small, of which the leakage of the monitoring hole S4 treated by the high pressure rotary jetting bored pile was the largest, and the leakage occurred more easily in the depth of 8 ~ 25m , The depth of the leakage rate and permeability coefficient of the depth than other depths, the joints were done by high pressure rotary jet grouting pile processing monitoring hole S16 ~ S20 in the depth of 35 ~ 55m range also have the above phenomenon; five joints There is no seepage abnormal phenomenon in the monitoring holes that have not been treated by high pressure rotary jet grouting bored pile.