深基坑锚杆改性水泥浆液特性试验研究

Research on the Characteristics of Rapid-hardening and High-strength Grouting Mortar in Deep Foundation Pit

为更好地解决深基坑工程中锚杆锚固力不足和养护周期长等问题,对传统纯水泥浆液掺入外加剂进行了改良设计,通过抗压强度测试、收缩特性分析和微观特性研究等手段对改性水泥浆液进行了研究。研究结果表明:①改性浆液7 d抗压强度为23.32 MPa,28 d抗压强度为28.06 MPa,可达同水灰比无外加剂强度的1.434倍。②改性浆液微膨胀特性显著,微膨胀率为0.314%,可达同水灰比无外加剂的1.82倍。③XRD测试结果表明硅酸三钙M3和钙铁石物质成分对改性浆液抗压强度影响显著,两种物质含量之和越大,以及明矾的掺入,抗压强度可显著提高。④SEM测试结果表明加入外加剂后,浆液内部结构出现了"针状"和"丝状"晶体,且相互交织较为紧密,大孔数量大幅减少,整体内部构造更为均匀合理。

In order to solve the problems that the hardening time is long and anchoring force is insufficient in deep foundation pit engineering,the traditional bolt grouting material with admixture was improved design,the rapid-hardening and high-strength grouting mortar was researched by intensity,shrinkage characteristics and microcharacteristic analysis. The results showed that ① the modification slurry intensity of 7 d was 23. 32 MPa,the intensity of 28 d was 28. 06 MPa,and it was 1. 434 times of the pure slurry with the same water cement ratio; ②the micro expansion characteristics of modified slurry was significant,the micro expansion rate was 0. 314%,and it was 1. 82 times of the pure slurry with the same water cement ratio; ③ the results of XRD test showed that the compressive strength of modified slurry was effected great by tricalcium silicate（ M3） and brownmillerite,the strength was increased with the incorporation of alum,and the increase of the sum of the two substances content; ④the results of SEM test showed that the ＂ needle＂ and ＂ filaments＂ crystal was appeared in internal structure after adding admixtures,the crystals was intertwined more chlsely,and the big hole was less,finally the overall internal structure is more uniform and reasonable.