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生物聚合物改良露天矿黏土抗裂性能研究

Study on anti-cracking properties of biopolymer-improved clay on open pit mine slopes

  • 摘要: 边坡稳定性在露天矿等工程中具有重要意义,在雨水的作用下边坡裂隙的形成和扩大可能导致边坡的失稳和破坏,而生物聚合物的引入可能对黏土边坡的干缩开裂性能产生显著影响。为探究生物聚合物在改善黏土边坡干缩开裂性能方面的效用,选取小龙潭露天煤矿的黏土作为研究对象,引入生物聚合物沙蒿胶和黄原胶进行改性处理。为评估不同掺量生物聚合物的抗裂效果和耐久性,开展了一系列干湿循环试验并记录含水率变化,通过PCAS软件处理对裂隙率、概率熵等指标进行定量分析。结果表明,生物聚合物的掺入会使裂隙显现时间提前,影响试样最终含水率,其中1%掺量的沙蒿胶能够提升黏土体53.5%的最终持水能力;生物聚合物的掺入显著降低黏土的裂隙率,但对概率熵的影响并不明显,首次干湿循环中1%掺量沙蒿胶和1%掺量黄原胶分别可使黏土裂隙率降低11.83%和16.39%,随干湿循环次数的增高,沙蒿胶试样抗裂能力逐渐降低,而黄原胶展现出一定的耐久性。基于实验结果利用XRD和SEM技术讨论生物聚合物影响黏土体抗裂性能的机理,发现生物聚合物的掺入并没有改变黏土组分,但生物聚合物能够通过静电键合和氢键键合与黏土矿物形成稳定联结,同时通过与水混合形成凝胶,微观层面上凝胶包裹和连接了土体颗粒,并填补了孔隙空间,有效地抵抗了黏土失水引起的抗裂张力。综合分析了沙蒿胶和黄原胶2种生物聚合物改良黏土抗裂性能的特点,为露天矿黏土边坡开裂问题的治理提供了借鉴和参考。

     

    Abstract: Slope stability is of great significance in open pit mines and other projects, while the formation and expansion of slope cracks under the action of rainwater may lead to slope instability and damage, and the introduction of biopolymers may have a significant effect on the drying and cracking properties of clay slopes. To investigate the effectiveness of biopolymers in improving the dry shrinkage cracking performance of clay slopes, the clay from the Xiaolongtan open pit coal mine was selected as the research object, and the biopolymers Artemisia sphaerocephala Krasch gum(ASKG) and Xanthan gum (XG) were introduced for the modification treatment. To evaluate the anti-cracking effect and durability of different dosages of biopolymers, a series of dry and wet cycle tests were carried out the change of water content was recorded, and the indexes such as fracture rate and probability entropy were quantitatively analyzed through PCAS software processing. The results showed that the incorporation of biopolymers would advance the time of fracture appearance and affect the final water content of the specimen, in which 1% dosing of ASKG could enhance the final water-holding capacity of the clay body by 53.5%; the incorporation of biopolymers significantly reduced the fracture rate of the clay, but the effect on the probabilistic entropy was not obvious, and the 1% dosing of ASKG and 1% dosing of XG in the first dry and wet cycle could reduce the fracture rate of the clay by 11.83% and 16.39%, respectively. 11.83% and 16.39%, with the increase in the number of wet and dry cycles, the cracking resistance of ASKG specimens gradually decreases, while XG shows some durability. Based on the experimental results, XRD and SEM techniques were used to discuss the mechanism of biopolymers affecting the cracking resistance of the clay body, and it was found that the incorporation of biopolymers did not change the clay components, but the biopolymers were able to form a stable association with clay minerals through electrostatic bonding and hydrogen bonding, and at the same time, they formed a gel by mixing with water, which encapsulated and connected soil particles at the microscopic level and filled up the pore space, effectively resisting the cracking resistance caused by water loss of clay body. It effectively resists the cracking tension caused by the water loss of clay. To resist the tension of clay water loss and cracking. This study comprehensively analyzes the characteristics of the two biopolymers, ASKG and XG, in improving the cracking performance of clay, which provides a reference for the management of clay slope cracking in open-pit mines.

     

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