拉力分散型锚杆应力分布特性对比试验研究

Comparative experimental study on axial force distribution of tension dispersed anchor

针对自由段及锚固段长度相同的普通拉力型锚杆及拉力分散型锚杆,设计并进行了对比张拉试验。采用在各锚杆锚固段粘贴电阻应变片的方式,获得锚杆锚固段轴力及摩阻应力在整个张拉受力过程中的分布状态及变化趋势。试验结果表明,相比普通拉力型锚杆,拉力分散型锚杆可以显著改善锚固段受力状态。砂性土中锚固段长度为16m的普通拉力型锚杆,随着张拉荷载的不断增加,杆体轴力能够逐步传递至锚固段末端,但锚固段末端利用效率相对较低,而拉力分散型锚杆锚固段轴力分布状态较普通拉力型锚杆有较大改善,直接传递至锚固段后端的轴力更大,且分布更加均匀。但由于拉力分散型锚杆长锚索单元自由段的自由度未能完全达到设计要求,其传递至锚固段的轴力存在一定损耗。

A set of comparative tests were designed and implemented for ordinary tension-type anchor and tension dispersed anchor with the same anchorage length. The distribution and variation tendency of axial force of anchorage is obtained by sensors along anchorage section. The test result shows that comparing to ordinary tension-type anchor,tension dispersed anchor could improve the stress state of the anchorage section significantly. For ordinary tension-type anchor with 16 m anchorage length,the axial force can be gradually transferred to the end of the anchorage bottom with increasing tensile force,but the force there is very small,while the distribution of axial force of tension dispersed anchor is more even that the axial force at the bottom is much higher. However,the axial force transferred to the end of the fixed section is always depleted somehow because the free section is not as free as design required.