高速公路拓宽工程硬路肩下土体注浆加固试验研究

Experimental research on injection process of soil under hard shoulder in freeway widening project

针对杭甬高速公路拓宽工程中,原硬路肩下局部土体需进行加固以达到底基层的设计要求的问题,首次提出了采用注浆法对硬路肩下土体进行加固,并对注浆工艺和加固效果进行了试验研究,具体内容包括:注浆孔布置、注浆材料、注浆方式、注浆控制参数、施工工艺及加固效果检测等。测试结果表明:采用注浆法加固后,硬路肩下土体弯沉值减小,回弹模量和剪切波速显著增大。注浆后土体回弹模量达到设计要求,施工过程基本不影响车辆通行,且与开挖翻造法相比可节约28%的工程造价。

Part of soil under the hard shoulder should be improved to reach the design standards of subbase in Hangzhou-Ningbo freeway widening project. Injection method is firstly put forward to improve the soil, and experimental study on injection process and effect is introduced in this paper. Researches about location of injecting hole, injection material and method selecting, injection controlling parameters and construction techniques are studied. In the end, two groups of testing are done to validate the reinforced effect. It is shown that as the deflection value decreases, modules of resilience and shear wave speed increase remarkably after injection. The resilient modulus of injected soil reaches the design standards. The advantage of this method is that it causes little influence on traffic and 28 percents of total engineering cost can be saved.