基于Hewlett方法的桩承式加筋路堤桩土应力比改进

Improvement on Pile-soil Stress Ratio of Pile-supported and Geosynthetics-reinforced Embankment Based on Hewlett Method

文中改进了拉膜效应对计算桩承式加筋路堤桩土应力比产生的影响,提出了新的计算方法。主要通过桩间加筋体的微分段静力平衡,然后,根据加筋体下的地基反力符合Winkler弹性地基模型的假定,耦合拉膜效应和加筋体上覆路堤的土拱效应可求得桩土差异沉降量以及网下桩土应力比。此外文中还分析了多种相关因素对桩土应力比的影响,也通过实例分析证明了该方法的可行性。结果表明:网下桩土应力比随土工格栅抗拉强度和填土高度的增加而增加,随桩间距的增加而减小,网上桩土应力比则反之;布桩形式不同,桩土应力比将随之改变,梅花形布桩时桩土应力比最大。该计算方法得到的桩土应力比计算值与实测值更加接近。

The influence of tensioned membrane effect on the calculation of pile-soil stress ratio of pile-supported and geosynthetics-reinforced embankment is improved,and a new calculation method is proposed.Primarily via static equilibrium equations of infinitesimal section of geogrid between the piles,according to the assumption that the reaction on foundation below the geogrid fit Winkler foundation model,and coupling membrane effect and soil arching effect of fill above the geogrid,the pile-soil stress ratios below the reinforcement net and differential settlement between piles and soil in the pile-supported reinforced embankment are obtained.In addition,this paper also analyzes the influence on the pile-soil stress ratio of various related factors,and proves the feasibility of this method through practical projects.The results show that the pile-soil stress ratios below the reinforcement net will increase with the increase of the tensile strength of geo-grids and the height of fill,and decrease with the increase of pile spacing,while the pile-soil stress ratios above the reinforcement net are the complete opposite of the former.The pile-soil stress ratio will change with different forms of placing pile,and the maximum stress ratio is obtained when arrange piles in the quincunxes.The calculated values of the pile-soil stress ratios is much closer to the measured ones.