松散回填层及深厚淤泥地基联合灌浆加固技术研究

Combined Grouting Technology in Loose Backfill Layer and Deep Silt Foundation Treatment

江苏某风电场升压站电缆沟地基为厚约3 m的土夹石回填层和15 m的淤泥层,因施工时回填层未分层碾压,淤泥层也未作处理,工程运行后出现了明显下沉,局部下沉量超过了30 cm,严重影响到电缆及设备的正常运行,亟需进行加固处理。针对该电缆沟回填层孔隙大、淤泥层深厚、地下管线复杂、施工空间受限、工期短,以及减沉加固效果要求高等工程特点,研究采用了"水泥膏浆+稳定性浆液"、"压力-流量双限控制"、"深-浅孔布孔"相结合的联合灌浆加固处理方法,以工后沉降为控制目标,对孔排距、灌浆压力和灌浆量进行了设计,对水泥膏浆和稳定性浆液进行了现场配比试验和灌浆施工,并对加固处理效果进行了分析评价。工后沉降监测表明,联合灌浆对于松散回填层及深厚淤泥地基加固处理效果较好,可为类似工程提供参考。

The cable trench foundation of a wind farm booster station in Jiangsu Province consists of backfill layer and silt layer. The thickness of earth rock backfill layer is 3 m, and the thickness of silt layer is 15 m. There is obvious subsidence after the project operation for the backfill layer which is not compacted and the silt layer is not treated during the construction. The local subsidence exceeds 30 cm which seriously affects the normal operation of the cable and the equipment, so the cable trench foundation needs to be reinforced urgently. The project has the characteristics of large pore in backfill layer, deep silt layer, complex underground pipeline, limited construction space, short construction period and high effect requirements. The combined grouting technology of "cement paste + stable slurry", "pressure & flow limit" and "deep-shallow hole" is adopted for the treatment. Taking the post construction settlement as the control objective, the hole spacing, grouting pressure and grouting volume were designed, field proportioning test and grouting construction of the paste and stability slurry were carried out, and the effect of reinforcement treatment was analyzed and evaluated. The monitoring of post construction settlement shows that the combined grouting is effective for the reinforcement of loose backfill layer and deep silt foundation, which can provide reference for similar projects.