塑料排水板堆载预压技术处理软土路基变形特性研究

Study on Measured Deformation and Settlement Prediction of Plastic Drainage Board under Surcharge Preloading

因在软土地基上修建公路时容易产生路堤失稳或沉降过大等问题,为此均要进行软基处理。介绍了采用塑料排水板堆载预压处理技术在南沙区某公路软土的路基处理,通过两个断面的工程现场监测,对软土地基处理后的地表沉降值、水平位移值和孔隙水压力值的变化规律进行了分析研究。结果表明,试软土地基处理后的沉降量差异明显,路中沉降大于路肩沉降,侧向位移主要发生在高程为(-4)~(-7)m内,在深度大于7 m时,随着深度的增加开始减小。由于塑料排水板的作用,加快了土层排水速度,孔隙水压力消散速度加快,软土地基强度也快速增加,有利于地基处理的施工安全。采用塑料排水板处理软土地基,软土地基的大部分沉降在填筑期基本完成,分层总和法计算工后沉降量少,稳定系数满足要求,能满足各项指标的规定。

When building highway on soft soil foundation, it is easy to produce problems such as embankment instability or excessive settlement. Therefore,soft foundation treatment should be carried out. Mainly introduces the construction monitoring design scheme and instrument embedding of soft soil treatment of a road subgrade in Nansha District, and arranges the variation laws of surface settlement value,horizontal displacement value and pore water pressure value of soft soil foundation treated with plastic drainage plate by using the field monitoring data of two sections. The settlement of the pavement in this test section is obviously different,and the settlement in the road is greater than that in the shoulder,mainly due to the large load in the road. In this project,the lateral displacement mainly occurs within the elevation of(-4) to(-7) m. When the depth is greater than 7 m,the value begins to decrease with the increase of depth. Due to the function of plastic drainage board,the drainage speed of soil layer is accelerated,the dissipation speed of pore water pressure is accelerated,and the strength of soft soil foundation is also increased rapidly, which is conducive to the construction safety of foundation treatment. The plastic drainage board is used to treat the soft soil foundation. This treatment method basically completes most of the settlement of the soft soil foundation during the filling period. The layered summation method calculates less post construction settlement, and the stability coefficient meets the requirements,which is beneficial to the highway construction. The method adopted to treat the soft soil is feasible and can meet the provisions of various indicators.