NH4^+对广州南沙原状软土工程性质的影响

Research on the effect of ammonium on the engineering properties of undisturbed soft soil of Nansha,Guangzhou

广州南沙地区地下水中存在着世界罕见的异常高NH4^+现象,NH4+浓度最高可达390 mg/L,该区处于大湾区的中心位置,已经或者即将建设大量工程。关于NH4^+对土的工程性质的影响研究目前比较薄弱。以广州地铁十八号线南沙段土体为例,探讨了NH4^+对土体工程性质的影响。与以往采用重塑土不同,本次使用的是南沙原状软土,经pH=1的HCl溶液酸洗、去离子水水洗以及NH4^+溶液渗透三步处理后,对试样进行固结和直剪试验。试验结果表明,随着NH4^+浓度升高,土体的压缩性增大,抗剪强度也得到提高。

The Groundwater of Nansha,Guangzhou is highly rich in ammonium that is very rare in the world, and the highest concentration of ammonium is up to 390 mg/L. This region is in a central position of Guangdong-Hong Kong-marco Greater Bay Area, where a large number of projects have been built or are about to be built. The influence of ammonium has not been specially concerned, taking Nansha Section of Guangzhou Metro line 18 as an example, the effect of ammonium on the engineering properties of soil has been researched. Unlike previous methods that remolded soil is applied as experimental material, after processed by pickling with pH=1 hydrochloric acid, washing with deionized water and permeation with ammonium solution, undisturbed soft soil of Nansha was used to do consolidation and direct shear test in this research. The result shows that an increased ammonium concentration leads to compressibility enhancement and higher shear strength of soil.