湿陷性黄土地区新建公路地基处理方案及工后沉降模拟计算  

Treatment Methods and Settlement Simulation Calculation of New Road Foundation in Collapsible Loess Areas

作　　者：肖春春 XIAO Chunchun(Gansu Highway Aviation Travel Longzhang Expressway Management Co.,Ltd.,Dingxi,Gansu 748100,China)

机构地区：[1]甘肃公航旅陇漳高速公路管理有限公司,甘肃定西748100

出　　处：《黑龙江交通科技》2024年第11期11-15,共5页Communications Science and Technology Heilongjiang

摘　　要：为了防止黄土湿陷沉降引起高填方路基失稳,以G8513高速公路K12+220~K12+860段填方路基为研究对象,利用自重湿陷量和总湿陷量判断了黄土的湿陷类型和湿陷等级,将地基划分为A段和B段。基于安全性、经济性、便于施工等原则,制定了湿陷性黄土地基的处理方案。对于A段,拟采用强夯法处理,处理范围应超出边坡坡脚3.0 m,单击夯击能取1200 kN·m,夯点布置形式为等边三角形,夯点中心间距取夯锤直径的1.2~2.0倍,分主夯、副夯、满夯三遍夯击,当最后两击的平均夯沉量<50 mm时即可停止夯击。对于B段,拟采用桩径0.5 m、桩间距1.2 m的灰土挤密桩处理.用沉管法成孔,桩体呈等边三角形布置,并在桩顶铺一层40 cm的灰土垫层。随后,利用数值计算软件建立高填方路基的模型,模拟其在灰土挤密桩处理后的沉降量,计算结果表明灰土挤密桩长度越大,工后沉降越小。当桩长>8 m,工后沉降变化不明显,故比选的最佳桩长宜取8 m。In order to prevent the instability of high fill subgrade caused by loess subsidence,the filling subgrade of the K12+220~K12+860 section of the G8513 Expressway was taken as the research object.The self weight subsidence amount and total subsidence amount were used to determine the type and grade of loess subsidence,and the foundation was divided into sections A and B.A treatment plan for collapsible loess foundation has been developed based on principles of safety,economy,and ease of construction.For section A,it is proposed to use the dynamic compaction method,which should extend beyond the foot of the slope by 3.0 m.The single click compaction energy should be 1200 kN·m,and the arrangement of compaction points should be an equilateral triangle.The center to center spacing of the compaction points should be 1.2~2.0 times the diameter of the compaction hammer.The compaction should be carried out in three stages:main compaction,secondary compaction,and full compaction.When the average settlement of the last two compaction is less than 50 mm,the compaction can be stopped.For section B,it is proposed to use lime soil compacted piles with a pile diameter of 0.5 m and a pile spacing of 1.2 m.The holes will be drilled using the sinking method,and the piles will be arranged in an equilateral triangle shape.A 40 cm lime soil cushion layer will be laid on top of the piles.Subsequently,a model of high fill subgrade was established using numerical calculation software to simulate its settlement after treatment with lime soil compaction piles.The calculation results showed that the longer the lime soil compaction piles,the smaller the post construction settlement.When the pile length is greater than 8 m,the post construction settlement change is not significant,so the optimal pile length for comparison should be 8 m.

关 键 词：湿陷性黄土 高填方 地基处理 换填 灰土桩 沉降模拟 

分 类 号：U416.1[交通运输工程—道路与铁道工程]