中文摘要：

中国西南地区正在或即将建设的高土石坝工程中,很多都涉及深厚覆盖层。在深厚覆盖层上建高土石坝,覆盖层坝基变形受力状态对坝体安全起重要作用。针对深厚砂砾石覆盖层取样困难而无法准确合理确定其天然密度,进而影响室内力学和渗透试验的开展,提出了利用旁压或动探试验间接推求天然砂砾石覆盖层密度的新方法,成功应用于乌东德深厚覆盖层工程特性研究,获得了覆盖层天然密度,较好的解决了深厚覆盖层工程特性测试难题。同时,针对新方法中存在的两个技术难题,基于室内模型试验验证了动力触探杆长修正系数的演化规律符合牛顿弹性碰撞理论,研制了一种的新型旁压仪的探头,实现了深厚覆盖层中旁压试验全过程测量。上述研究成果为进一步提升深厚覆盖层上高土石坝坝基变形预测与设计水平提供了重要技术支撑。

英文摘要：

For many high rockfill dams, which are constructed or will be constructed in Southwest China, deep overburden is one of the most complex engineering problems. The deformation and stress status play an important role in the safety of dams. For the traditional methods, because it’s almost impossible to collect gravel overburden layer samples, the original density cannot be determined exactly. Thus, it is very difficult to get the reliable mechanical and seepage properties of overburden layer in laboratory tests. A new method that indirectly calculates the original density of overburden gravel using pressuremeter tests (PMT) or dynamic penetration tests (DPT) is proposed. In the construction period of Wudongde, this method is successfully applied to the determination of the density of overburden layer. Furthermore, based on the indoor model tests, it is verified that the correction factor of rod length in DPT follows the description of Newton elastic collision theory. Therefore, a new pressuremeter probe with high pressure and side expansion is developed in order to conduct the whole-process pressuremeter tests on deep overburden. The proposed whole set method provides an important technical support for further studies on the engineering properties of deep overburden of dam foundation.