注浆钢花管加固技术在医院扩建工程深基坑的应用研究

Study on application of grouting steel pipe reinforcement technology in deep foundation pit of hospital expansion project

为有效防范填土深基坑变形过大对周边环境造成的安全风险,以山东济南某医院改扩建工程深基坑为研究背景,提出微型桩+预应力锚杆+钢花管水平注浆的组合支护体系,并根据以往注浆经验,对钢花管水平注浆的加固机理、注浆效果和注浆参数进行分析,以解决回填土深厚、场地空间狭小、周边环境复杂等支护技术难题。同时结合MIDAS/GTS有限元模拟,计算了钢花管注浆与未注浆的2种工况下填土深基坑的位移、内力变化情况,判断该支护体系应用于填土深基坑的支护效果,探究支护结构受力规律。结果表明:该支护体系受力合理,变性控制能力强,对肥槽填土基坑加固具有明显的优势和适用性;钢花管水平注浆加固后,回填土的位移大幅降低,变形量减少约49.5%,在保证基坑自身安全的同时,可减少施工对周边环境的损伤;监测结果显示基坑变形均控制在允许范围内,达到了预期的注浆效果,可为今后类似工程建设提供有益的技术支持和参考。

In order to effectively prevent the safety risk caused by excessive deformation of filled deep foundation pit to the surrounding environment, taking the deep foundation pit of a hospital reconstruction and expansion project in Jinan,Shandong Province as the research background, this paper puts forward the combined support system of micro pile +prestressed anchor rod + steel flower pipe horizontal grouting. According to the previous grouting experience, the reinforcement mechanism, grouting effect and grouting parameters of horizontal compaction grouting are analyzed to solve the support technical problems such as deep backfill, narrow site space and complex surrounding environment. At the same time, combined with MIDAS/GTS finite element simulation, calculate the displacement and internal force changes of filled deep foundation pit under two working conditions of steel pipe grouting and non grouting, judge the support effect of the support system applied to filled deep foundation pit, and explore the stress law of the support structure. The results show that: The support system has reasonable stress and strong variability control ability, and has obvious advantages and applicability for the reinforcement of filling foundation pit of fertilizer tank;After the horizontal grouting reinforcement of the steel pipe, the displacement of the backfill is greatly reduced, and the deformation is reduced by about 49.5%. While ensuring the safety of the foundation pit, it can reduce the damage to the surrounding environment caused by the construction;The monitoring results show that the deformation of foundation pit is controlled within the allowable range, and the expected grouting effect is achieved, which can provide useful technical support and reference for similar engineering construction in the future.