关键词: 桩承式加筋路堤受力性状比较复杂, 土拱效应对路堤的承载变形性状具有重要影响。通过三维土拱效应模型试验, 研究桩-土相对位移、路堤高度、桩帽净间距和水平加筋体拉伸强度等因素对桩土应力比及路堤沉降的影响。结果表明：土拱效应发挥程度与桩-土相对位移密切相关, 存在一个临界桩-土相对位移使得桩土应力比达到最大值, 该临界桩-土相对位移约为6～8 mm。路堤高度与桩帽净间距之比越大, 桩土应力比越大, 路堤顶面差异沉降越小；桩帽宽度与桩帽净间距之比越大, 桩土应力比越大, 路堤顶面差异沉降越小。设置水平加筋体能有效提高桩土应力比并减小路堤顶面沉降；路堤越低, 水平加筋体对桩土应力比的提高作用及对路面沉降的减小作用越明显；水平加筋体拉伸强度越高, 这种作用越明显。桩承式加筋路堤三维土拱效应等沉面高度与桩帽净间距之比约为3.5。

Abstract: Soil arching has a notable influence on the behavior of piled reinforced embankment for its mechanically complex nature. A series of 3D model tests are conducted to explore the influence of the pile-soil relative displacement, embankment height, pile-cap spacing and horizontal reinforcement tension strength on the stress concentration ratio as well as the embankment settlement. The test results show that: soil arching is closely related to the pile-soil relative displacement and there exists a critical pile-soil relative displacement of approximate 6 to 8 mm which makes the stress concentration ratio reaching its maximum value. The bigger the ratio of embankment height is to the pile-cap clear spacing, the bigger the stress concentration ratio and the smaller the differential settlement on the surface of the embankment are; a bigger ratio of the cap width to the pile-cap clear spacing will result in a bigger stress concentration ratio and a smaller differential settlement. The installation of horizontal reinforcement within the embankment will effectively increase the stress concentration ratio and decrease the surface settlement; a low embankment as well as high tension strength of the reinforcement will enhance the function of the horizontal reinforcement. The equal settlement plane height is about 3.5 times the pile-cap clear spacing for 3D soil arch in piled reinforced embankments.

Key words: piled reinforced embankment, 3D soil arching, model test, soil stress concentration ratio, equal settlement plane