傍山高陡填方软土路基的处治设计

宁台温高速公路瑞安龙头至苍南分水关段第九合同段第2号工点是一傍山高陡填方软土路基。该工点地质条件特殊,半幅路基位于有一定斜坡的地质条件较好的山坡上,而另半幅路基位于海相沉积的水田内,上部有3.2m～7.2m的淤泥层,淤泥层底部横坡较大;边坡处最大填方高度约20m,存在横向滑动的趋势及不均匀沉降。为了解决路基的稳定及沉降问题,在该处路基设计中采用了锚索抗滑桩、反压护道及排水、分层铺设土工格栅等方法进行综合处治,通过近2年多的监测,傍山高陡软土路基的水平位移速率已经稳定,沉降也逐渐缓和。通车2 a多时间内,经受了多次台风暴雨袭击,路基一直处于稳定状态,充分说明本工点处理方案是成功的,达到了安全、稳定的目的。

TREATMENT DESIGN OF THE MOUNTAINSIDE HIGH STEEP FILL SOFT SOIL SUBGRADE

The author in this paper introduces the treatment design of the mountainside high steep soft soil subgrade of No.2 worksit of No.9 contract section of Ruian Longtou-Cangnan Shuiguan in Ning-Tai-Wen express highway.This geology condition of this worksite is special,half of the subgrade Is located on a slope hillside with better geology condition;and the other half is located in the paddy field with mainre deposit,the thickness of the silt seam is 3.2~7.2m and its bottom transvers slope is a little big;the maximum height of fill at the slope is 20m or so,it existences transvers skidding tendency and uneven subsidence.In order to solution the problem of subgrade stabilizatin and subsidence,in the design,these methods as anchor-cable anti-slide pile,counter weight slope protection,discharging etc.are used to synthetically treat.Through nearly more than 2 years of monitoring,the horizontal departure speed of the mountainside high steep soft soil subgrade already stabilized and the subsidence is also gradually relaxes.the roadbed is always at the steadystate in 2004~2006 when the express highway is opened and suffers the typhoon rainstorm attack many times,it fully proves the treatment design of this worksite is successful and achieves the safely,the stable goal.