北石窟寺平顶窟顶板裂隙灌浆黏接材料性能研究

Research on the properties of grouting bonding materials for cracking of roof rock mass of the flat top cave of North Grottoes

平顶窟是北石窟寺最典型的洞窟形制之一,平顶窟顶板沉积层界面强度低且易风化开裂。为有效提高顶板开裂病害的灌浆黏接加固效果,选用烧料礓石和砂岩粉末为主材,掺入不同浓度有机硅改性丙烯酸溶液和不同含量玻璃微珠配置浆液测试其流动性能、基本物理力学指标、微观形貌及黏接性能,发现掺入0%~1.0%浓度硅丙或0%~0.5%含量玻璃微珠,浆液流动度和可灌性满足需求的前提下,波速、抗折、抗压和黏接抗拉强度等均显著提高,收缩率和密度降低。微观试验表明,烧料礓石通过水化和气化反应生成β-CaO·SiO_(2)·n H_(2)O,2CaO·Al_(2)O_(3)·SiO_(2)·n H_(2)O及CaCO_(3),提高浆液强度,硅丙溶液使得浆体微观形貌从松散的颗粒状改变为紧密的片层状,玻璃微珠可填充于浆体原有的较大孔隙中,增强浆体的连续性。烧料礓石和砂岩粉末1∶1,掺入浓度0.5%的硅丙溶液和0.25%含量的玻璃微珠的浆液,其各项指标最佳,在砂岩石窟平顶窟顶板层间裂隙灌浆黏接中具有广泛的应用前景。

The flat top cave is one of the most typical cave shapes of the North Grottoes.The interface strength of the sedimentary layer on the top of the flat top cave is low and easy to weather and crack.In order to effectively improve the effect of grouting bonding and reinforcement for roof cracking diseases,sintered stone and sandstone powder were selected as the main materials,mixed with different concentrations of organosilicon-modified acrylic acid solution and different contents of glass microbeads to configure the slurry to test its flow properties,basic physical mechanics indexes,micromorphology and adhesive properties.It is found that the wave speed,flexural resistance,compressive resistance and bonding tensile strength are all significantly improved,and the shrinkage rate and density are reduced that the slurry fluidity and pourability met the requirements by adding 0%-1.0%concentration of silicone-acrylic or 0%-0.5%content of glass beads.Microscopic experiments show that the sintered sintered stone generatesβ-CaO·SiO_(2)·nH_(2)O,2CaO·Al_(2)O_(3)·SiO_(2)·nH_(2)O and CaCO_(3)through hydration and gasification reactions,which improves the strength of the slurry.Changed to a compact lamellar shape,the glass microbeads can be filled in the original larger pores of the slurry,which enhances the continuity of the slurry.The sintered stone and sandstone powder are 1∶1,mixed with 0.5%silicone-acrylicand 0.25%glass microbeads,and the indicators are the best.It has broad application prospects in the grouting bonding of cracks between the roofs of flat top cave in sandstone caves.