高应变动力试桩法土阻力波的理论计算及测量

Calculation and Measurement of Soil Resistance Wave in High Strain Dynamic Testing

土阻力波是由于桩顶打击力所产生的应力波在桩身内传播,导致桩身与桩周土发生相对位移后产生的;根据波动方程理论,桩身内应力波可分离为上下行波两类;土阻力波与阻抗不连续面的反射波均包含于上行波中,仅当阻抗变化已知时,可准确计算出土阻力波;桩端土阻力波的计算因桩底反射波的干扰而存在误差;桩身阻抗存在明显差异的灌注桩,不应采用土阻力波理论计算土阻力;桩身材料物理学性质的不确定及现场操作不规范是土阻力波计算误差其他来源。

When the stress wave that is caused by transient striking force,passes through the pile,and initiates the placement between the pile and surrounding soil,the soil resistance wave is made. According to the theory of wave equation,inner force wave can be separated two parts,upwards wave and downwards wave. The soil resistance waves and reflection waves which caused by impedance discontinuity in pile are included in upwards wave. If we actually understand the variety of impedance of pile,the value of soil resistance wave can be calculated accurately. The value of toe resistance wave is uncertain because of the toe reflection wave. The theory of soil resistance should not be used in calculating soil resistance wave on place-cast pile which has serious defect to calculate the. Uncertain physical properties of pile and non-standardly site-working are the other sources of error in soil resistance wave measurement.