力量速度法和力量平方法量测动力触探锤击能试验研究

Experimental study on the measurement of dynamic penetration test hammer impacting energy by force-velocity method and force square method

动力触探指标修正、试验稳定性、锤击数转化关系与有效锤击能密切相关。在探杆杆顶处和探头处安装应变片和加速度传感器,量测不同探杆长度下的重型、超重型动力触探锤击能。结果表明:当探杆中单个探杆较短、接头数多时,使用积分域为(0、2l/c)的力量平方法(F2法)计算所得探杆锤击能与实际锤击能相差较大(l为探杆长度,c为波的传播速度)。由于原位试验时干扰因素过多,力量速度法(FV法)选取首个极值和F2法选取锤击轴力首次穿过0点时作为锤击能量的积分结束时间计算锤击能更为合理。随着探杆长度的增大,达到探头处的锤击能量呈线性减小。3、5、8、11 m杆长下的重型和超重型锤击数转化系数分别为2.285、2.160、2.440、2.810,与超重型和重型的总势能比基本一致。

The dynamic penetration index correction, test stability and relationship of blow-counts are closely related to the effective hammer impacting energy. Strain gauges and acceleration sensors were installed at the top of the probe rod and the probe, and the hammer energy of heavy and super-heavy dynamic penetration under different probe rod lengths was measured. The results show that when the single probe rod in the probe rod is short and there are many joints, the hammer energy of the probe rod calculated by the force square method(F2 method) with an integral domain of(0, 2l/c) differs greatly from the actual hammering energy, where l is probe rod length, c is wave velocity. Due to too many interference factors in the in-situ test, it is more reasonable to the force velocity method(FV method) that selects the first extreme value and the F2 method selects the time when the hammering axial force first passes through the zero point as the integral end time of hammering energy to calculate the hammering energy. As the length of the probe rod increases, the hammer energy reaching the probe decreases linearly. Blow-count converting coefficients for heavy and super-heavy hammer numbers under the rod lengths of 3, 5, 8 m, and 11 m are 2.285, 2.160, 2.440, and 2.810, respectively, which are basically consistent with the total potential energy ratio of super-heavy and heavy hammer.