加筋地基土压力测试与机理分析

Measurement of soil pressure in geobelt-reinforced foundation and analysis of reinforcement mechanism

在素垫层内铺设土工材料加筋后,筋土的界面摩擦作用使加筋垫层的模量提高、应力扩散范围增大,有效发挥下卧土层的承载力、减小地基沉降。通过土工带加筋现场原位试验垫层底的土压力分布测试与结果分析得出:加筋薄垫层(Z/B=0.2)地基垫层底土压力分布是不均匀的,应力集中于基础的边缘,基础中心下应力较小。加筋地基强度和变形与加筋参数有关,通过引入应力扩散系数,分析不同加筋参数下加筋地基的应力扩散能力,研究筋土界面摩擦作用的应力扩散加筋机理,结合工程实际提出太原地区应力设计扩散角取值范围,为加筋地基的设计提供理论依据。

After geobelt is included into soil to provide lateral confinement through geobelt-soil interface friction under loading, the modulus ratio of the reinforced cushion to the underlying soft soil stratum increases, the stress distribution capacity of reinforced cushion is strengthened, the bearing capacity of soft soil under reinforced cushion can effectively function, and the foundation settlement decreases. The measurement of soil pressure under reinforced cushion is carried out based on different reinforcement parameters. The test results show that the soil pressure under reinforced cushion is not even. The stress under reinforced cushion concentrates on the edge of foundation, and the stress in the center is less than that at the foundation boundary. The reinforced foundation strength and deformation are relevant with the reinforcement parameters. The stress diffusion capacity of reinforced cushion is analyzed by stress diffusion coefficient under different reinforcement parameters. The reinforcement mechanism can be described as follows： the interface frictions function between the geobelt and the soil, the friction force direction continuously changes, and the stress spreads to the both sides. Based on the practical conditions of the project, the design diffusion angles are put forward for Taiyuan city.