Research on Soil Instability Characteristics and Prevention Measures of Row Pile Support in Expansive Soil Deep Foundation Pit

The characteristics of expansive soil, such as overconsolidation, multi fissure and shrinkage cracking due to water expansion and water loss, are called "hidden disasters" by the geotechnical engineering community. Its damage mechanism has become an important technical problem that the underground space engineering must face and solve. The expansive soil is mainly distributed in the eastern region in Chengdu. According to the investigation, the soil collapse between the supporting piles often occurs in the construction of the deep foundation pit of the subway station in the eastern region, causing safety accidents such as personal injury or equipment damage. In this paper, taking the stability of soil between piles of deep foundation pit excavation and support piles of the East extension line station of phase II of Chengdu rail transit line 17 as the research object, the instability characteristics of soil between piles of deep foundation pit excavation and support piles of railway stations on expansive land in Chengdu area are systematically studied by means of field investigation, field measurement analysis, instability characteristics analysis and calculation and derivation of soil stability between piles, and the characteristics and causes of soil instability between piles of deep foundation pit excavation and support piles of railway stations on expansive land are proposed, and put forward prevention measures and suggestions.