强风化千枚岩填筑路基改良技术研究

在山区高速公路穿越的大量强风化千枚岩分布区域,为解决路堤填料缺乏,弃土占用农田的问题,同时为了节省投资和保护环境,应用强风化千枚岩作为路基填料。在强风化千枚岩原岩基本物理力学试验及填料的工程特性试验基础上,对加州承载比（CBR）不满足高速公路路基填筑力学性能的填料采用水泥进行改良,分析了不同水泥剂量填料的击实性能、级配特性及工程特性,并在十堰至天水高速公路K22＋720～K22＋920段现场铺筑试验路,论证强风化千枚岩改良技术的可行性。研究结果表明：采用水泥剂量（质量分数）3%,4%,5%,6%改良后,强风化千枚岩填筑的路基力学性能随着水泥剂量的增加而增加,CBR值和回弹模量都能够满足高速公路路基填筑要求。

Research on Improvement Technology of Filling Subgrade with Highly-weathered Phyllite

In the area with lots of highly-weathered phyllites that the mountainous expressway run through,to solve the problems of the shortage of filling soil and using farmland soil or deserted soil from other places,and to protect the environment and save investment,the in-situ highly-weathered phyllites were applied as the filling material instead of the general soil.Based on both the physics and mechanics experiments and the engineering characteristic experiments of the phyllites,different contents cement was mixed into the phyllites to form a new kind of filling material.The material could satisfy the requirement of the highway standard through mixing the cement.The compaction performance,the graduation characteristics and the engineering characteristics of the filling material under different cement contents were analyzed.The test road being from section K22+720 to section K22+920 of Shiyan-Tianshui Expressway were selected to validate the feasibility of the reinforcement technology.The contents of mixing cement were from 3% to 6% at interval of 1%.The results show that the mechanics performance of the filling material can be reinforced by mixing the cement into the phyllites and can satisfy the requirement of the highway standard.With the increase of the mixed cement content,both the CBR value and the modulus of the filling material increase.