带排水功能的半刚性桩实例应用研究及探讨  

Research and Discussion on Application of Semi Rigid Pile with Drainage Capability

作　　者：陈明晓 廖萍 

机构地区：[1]广东省南粤交通投资建设有限公司,广东广州510101 [2]广东省航运规划设计院有限公司,广东广州510050

出　　处：《中国公路学报》2017年第11期27-35,共9页China Journal of Highway and Transport

摘　　要：为了充分利用复合地基桩间软土的强度增长,对超软弱土地区中快速完成高填土路基的填筑提供一种新的软基处理方法,采用带排水功能的半刚性桩进行软基处理,通过对水泥砂浆的配合比、土工布的透水性及隔离固体颗粒特征等桩体材料试验,在地面上及地下分别进行试桩,以研究材料成桩后水泥砂浆的凝固特征、桩体强度特征及抗弯折性能。借助南沙公检法配套市政道路滑塌区软土中完成填土高度约10 m的路基填筑的实施案例,通过施工过程中软土的侧向位移、沉降、孔隙水压力及土压力监测,软土的原位测试及桩的检测等试验数据,分析路基填筑完成后的软基处理效果,并根据桩的承载力检测及桩土应力比监测初步探索其设计。研究结果表明:通过带排水功能的半刚性桩可加快路基的填筑,从而加速软土的强度增长及缩短软基的工后沉降时间;带排水功能的半刚性桩在凝固过程中,水泥与砂表现出明显的分选性,桩周水泥含量显著增多,桩体径向抗压强度逐渐增大,桩体表现出类似刚性桩的特征;桩周土工布发挥了明显的排水固结作用,使软基发生了较大的沉降,桩周软土强度显著增长,提高了桩周摩阻力,并充分发挥桩间土的承载能力,且桩能较好适应软土的大沉降变形,桩体表现出类似柔性桩的特征;按现行的复合地基设计理论,其承载力无法满足填土荷载的要求,而采用软基的沉降及稳定性进行设计更为合适;研究为探索复合地基设计理论提供了一种新的思路。To make full use of the increasing strength of the soil between composite foundations piles,and provide a new soft foundation treatment method for the rapid completion of filling the high subgrade in the super soft soil area.The semi rigid pile with drainage capability was used to improve the soft foundation. Through the tests on the ratio of cement mortar and the permeability of earthwork cloth and the characteristics of solid particles,the test pile was carried out on the ground and underground to investigate the solidification characteristics of the cement mortar,the strength characteristics and bending resistance of the pile.In view of the subgradefilling with the height of over 10 min the soft soil area of the sliding collapse zone of the municipal administration path supported by Nansha procuratorial organs and people’s courts,the effects of soft foundation treatment were analyzed by test data including the lateral displacement,settlement,pore water pressure,earth pressure monitoring,the in situ test data of soft soil and the pile detection.The preliminary researches on its design method dependent on the pile bearing capacity test and pile-soil stress ratio were conducted.The results show that the semi rigid pile with drainage capability can accelerate the filling of the subgrade to increase the strength of soft soil and shorten the time of settlement of the soft foundation.During the solidification process of the semi rigid pile with drainage capability,there is a clear separation between cement and sand.Pile cement content significantly increases,and pile radial compressive strength increases gradually.The body presents the similar characteristics of rigid pile.Earthwork cloth around pile plays a role in drainage consolidation,leading to the large settlement.The strength of soft soil around pile dramatically increases,so the frictional resistance around pile in the soft foundation is improved.The bearing capacity of the soil between piles can be given full rein,and the pile can adapt to soft soil settle

关 键 词：道路工程 半刚性桩 监测检测 水泥砂浆布袋桩 超软弱土 

分 类 号：U416.12[交通运输工程—道路与铁道工程]