桩承式加筋路堤张力膜效应模型试验研究

在桩承式加筋路堤设计计算及工程实践中，筋材的受力计算是具有争议且亟待解决的问题，然而，现有的研究很少关注桩承式加筋路堤中筋材应变的空间分布形式和三维模式下筋材的受力特征。采用自行研制的设备，以桩间距为变量，针对桩承式加筋路堤中筋材张力膜效应进行了物理模拟试验。试验中通过气压施加荷载，对筋材竖向变形和不同位置筋材应变进行观测。结果表明，张力膜效应下筋材应变和受力很不均匀。正方形布桩情形下，加筋材料的空间变形形态可采用空间抛物面与抛物柱面的组合来模拟。正方形布桩情形下假定筋材上所有荷载全部由相邻桩之间的4条筋带承担，得到的筋材受力计算值明显偏大。在模拟试验结果基础上，初步提出了考虑筋材三维空间变形的拉力计算方法。

Model tests of tensile membrane effect of geosynthetic-reinforced piled embankments

Calculation of the deflection and tension of the membrane elements in geosynthetic-reinforced and piled (GRP) embankments is a controversial issue yet to be resolved. However, little attention was paid to the evaluation of the strain distribution in geosynthetic reinforcements and the three-dimensional displacements of the geosynthetic materials. Physical model tests of membrane effect of geosynthetic reinforcement in GRP embankments with different pile spaces were carried out using a self-designed equipment. In the model tests, the geosynthetic reinforcement was loaded by applying air pressure, the strains in geosynthetic reinforcement were monitored in different locations. It is shown that: the strain and tension of geosynthetic reinforcements are unevenly distributed, and the three-dimensional deformation of the geosynthetic above square-distributed piles can be represented by a parabolic face and a parabolic cylinder; the applied loads are carried mainly by 4 tensile strips between two adjacent piles, and the calculated tension in geosynthetic reinforcements is much larger than the experimental results. Based on the modeling test results, a new calculation method for the tension in geosynthetic reinforcements is tentatively presented in this paper.