循环荷载及静载下土工格室加筋路堤模型试验研究

为探究土工格室加筋路堤在循环荷载及静载下的各种性能，利用美国GCTS公司的USTX-2000加载装置进行加载，通过改变加筋层数、格室高度，格室焊距对土工格室加筋路堤进行一系列模型试验。对各种工况下加筋路堤极限承载力、长期循环荷载及固定振次循环荷载后极限承载力的变化进行研究。试验表明，土工格室加筋能显著提高地基极限承载力并能显著减小坡顶和坡中临界破坏时的法向累积变形，在加筋间距一定的情况下，加筋层数增加和格室高度增大均可不同程度提高极限承载力并减小临界破坏时坡顶法向累积变形，格室焊距的减小也可在一定程度提高极限承载力，格室焊距对边坡法向变形影响不大；长期循环荷载下固定间距加筋层数对路堤竖向累积沉降量影响不大，而对边坡坡顶法向累积变形有一定影响，格室高度增大和格室焊距减小均可不同程度减小路堤竖向累积沉降量和坡面法向累积变形；越靠近加载点处，路堤土压力值受加筋影响越显著，加筋提高了土体刚度和密实度，使加筋路堤土压力值较无筋路堤明显增大；对于无筋路堤，改变动载幅值和振次均导致振后极限承载力有不同程度的降低，而对于加筋路堤，当动载幅值≥30 kPa或动载振次≥1 000时，振后极限承载力均有不同程度的提高。

Model tests on geocell-reinforced embankment under cyclic and static loadings

To investigate the performance of reinforced embankment under cyclic and/or static loading, a series of model tests is performed on the geocell-reinforced embankments with various reinforced layers, geocell heights and welding distances, using the loading device of USTX-2000 developed by the GCTS company. The ultimate bearing capacities of the reinforced embankment subjected to both long-term cyclic loading and fixed-number cyclic loading are determined under various operating conditions. The experimental results show that geocell can significantly increase the ultimate bearing capacity of foundation soils and observably reduce the normal accumulated deformation at the critical failure of the top and the middle of slope; for a certain reinforcement spacing, with the increase of the number of reinforcement layers and the height of the geocell, the ultimate bearing capacity can be improved to different degrees and the normal accumulated deformation of critical failure of the top of slope can be reduced; the decrease of the weld space of geocell can also improve the ultimate bearing capacity, and the weld space of geocell has trivial effect on the normal deformation of slope. The number of reinforced layers in fixed spacing has little effect on the vertical cumulative settlement of embankment and can influence the normal accumulated deformation of the top of slope under long-term cyclic loading; the increase of the height of geocell and the decrease of weld space of geocell can reduce the vertical cumulative settlement of the embankment and the normal accumulated deformation of the slope to different degrees. The less the distance to the point of loading, the more significant the influence of reinforcement on the soil pressure of embankment, and the reinforcement increases the stiffness and compactness of soil, so that the soil pressure of the reinforced embankment increases more obviously than that of unreinforced embankment. For the unreinforced embankments, the change of dynamic load amplitude and vibration number can result in the reduction of the ultimate bearing capacity after vibration. For the reinforced embankment, when the dynamic load amplitude is greater than or equal to 30 kPa or the number of dynamic load vibration is greater than or equal to 1 000, the ultimate bearing capacity after vibration is improved.