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采取加固措施可提高土体抗剪强度、减小变形等。采用聚氨酯高聚物胶凝堆石料加固土石坝以改良堆石料强度、变形特性。开展了聚氨酯胶凝堆石料三轴剪切试验研究,结果表明:聚氨酯胶凝堆石料偏应力-轴向应变曲线具有明显的非线性,抗剪强度提高;采用抛物线拟合偏应力-轴向应变曲线,可反映其应变软化和应变硬化,并得到初始弹性模量随聚氨酯含量的提高而提高;聚氨酯泡沫填充堆石颗粒间孔隙并将堆石颗粒黏结在一起,减少颗粒破碎、颗粒重排列,使堆石料剪缩特征减弱,当聚氨酯含量高时表现出剪胀;聚氨酯增加了堆石料准黏聚力,对内摩擦角无明显影响。通过有限元方法对堆石坝变形和稳定性进行分析,结果表明,聚氨酯加固堆石坝可减少边坡浅层滑动,增大滑弧深度,提高坝坡稳定安全系数。
Reinforcement measures can be taken to improve soil shear strength, reduce deformation and so on. Adopt polyurethane high polymer gelling material to reinforce earth dam to improve the strength and deformation characteristics of rockfill materials. The triaxial shear tests on polyurethane gelable stones were carried out. The results show that the deviator stress-axial strain curves of polyurethane gelled rockfill materials have obvious nonlinearity and the shear strength is improved. The parabolic fitted deviatoric stress-axial strain Curve can reflect the strain softening and strain hardening, and get the initial elastic modulus increased with the increase of polyurethane content; polyurethane foam filled the pores of rockfill particles and the rockfill particles together, reducing the particle crushing, particle rearrangement, So that the shrinkage characteristics of the rockfill materials weakened, showing a dilatancy when the polyurethane content is high; polyurethane increased the quasi-cohesion of rockfill material, no significant impact on the internal friction angle. The deformation and stability of rockfill dams are analyzed by finite element method. The results show that the polyurethane rockfill dam can reduce the shallow slip of the slope, increase the arc depth and improve the safety factor of dam slope.