静态破碎剂对钢管径向膨胀压应力试验

为考察静态破碎过程中径向膨胀压应力沿孔深方向的分布,探究孔径、孔深、约束程度对径向膨胀压应力大小的影响规律,利用无缝钢管模拟钻孔,采用电阻应变片法测量了静态破碎剂在结硬过程中对21个试件的径向膨胀压应力.根据“钢管混凝土套箍理论”,将钢管截面面积与静态破碎剂截面面积的比值定义为约束程度.试验结果表明:静态破碎剂产生的径向膨胀压应力沿孔深方向并非均匀分布,一般钻孔中部和底部的膨胀压应力大于上部；孔径越大,孔底部与上部的径向膨胀压应力相差越大,相同时间内孔中部和底部所能达到的膨胀压应力越大,孔口溢出的破碎剂越多；孔深和约束程度对膨胀压应力的发展速度影响不大,孔中部和底部静态破碎剂所产生的膨胀压应力随着孔深或约束程度的增大而增大；选用合适孔深、较大孔径更有利于静态破碎剂发挥其膨胀潜力.

Experimental study on radial expansion compressive stress of steel tube with static crushing agent

To investigate the distribution of radial expansion compressive stress along the direction of hole depth in static crushing process and explore the influences of hole diameter, hole depth, and constraint degree on radial expansion compressive stress, the radial expansion compressive stress of 21 specimens during static crushing process was measured by means of resistance strain gauge method by using seamless steel pipe to simulate drilling. According to the theory of hoop of concrete filled steel tubular, the ratio of sectional area of steel tube to sectional area of static crushing agent was defined as constraint degree. Experimental results show that the radial expansion compressive stress produced by static crushing agent was not uniformly distributed along the direction of the hole depth, and the expansion compressive stress in the middle and bottom of the hole was generally greater than that in the top. With the increase of the hole size, the difference between the radial expansion compressive stress at the bottom of the hole and the upper part was more significant, the expansion compressive stress at the middle and bottom of the hole in the same time became larger, and more crushing agent overflowed the orifice. Hole depth and constraint degree had little influence on the expansion compressive stress, and the expansion compressive stress generated by static crushing agent in the middle and bottom of the hole increased with the increase of hole depth or constraint degree. The selection of suitable hole depth and larger hole size is more conducive to static crushing agents for developing their expansion potential.