针对传统黏土-水泥喷涂堵漏风材料(CCC)强度差、易开裂、堵漏风效率低的问题，提出经黄原胶(XG)和氧化镁(MgO)改性制备黏土-水泥基新型喷涂堵漏风材料(XM-CCC)。通过析水率测试、浆液时变性和流变性试验，确定了0.6的最佳水固质量比和20%(质量分数)最佳黏土掺量。通过力学性能试验和限制膨胀率试验确定了1.5%(质量分数)的XG最佳掺量和5%(质量分数)的MgO最佳掺量，XM-CCC的7 d抗压强度达到25.33 MPa、抗折强度达到9.18 MPa，21 d限制膨胀率稳定在0.028%左右。基于此，结合表征手段对XM-CCC的形成机理和堵漏风机理进行探究。结果表明，XG中羟基、羧基等活性官能团与浆液颗粒表面的Ca²⁺发生螯合作用，黏土颗粒被束缚在水泥颗粒的水化产物间，促进了XM-CCC力学性能的提升。MgO水化生成的六方板状Mg(OH)²晶体支承在体系的孔隙中，提高了XM-CCC的抵御收缩能力。孔隙结构方面，XG改变了XM-CCC的孔结构，降低了平均孔径;Mg(OH)²晶体充填孔隙，产生的晶体生长压力可以抵御孔隙压力，保持基体不开裂，同时降低了孔隙率;XG与MgO的共同作用使XM-CCC的气体渗透系数仅为1.47×10^-12，远低于围岩渗透系数。经济性上，XM-CCC取材方便、制作简单，成本较低，喷涂工艺简单灵活。现场应用结果表明，XM-CCC的涂层均匀、完整，抗开裂与封闭性能较好，具有良好的应用前景。

Aiming at the problems of poor strength,prone cracking,and low gas sealing efficiency of traditional clay cement composite gas sealing materials (CCC),a new type of claycement based spraying material of gas sealing (XM-CCC) modified by xanthan gum (XG) and magnesium oxide (MgO) was prepared.Through water separation proportion test,slurry time varying and rheological tests,the best water solid ratio of 0.6 and the best clay content of 20% were determined.Through mechanical performance test and constrained expansion test,the optimal amount of XG 1.5% and MgO 5% were determined.The compressive strength of XM-CCC (7 d) reaches 25.33 MPa,the flexural strength reaches 9.18 MPa,and the constrained expansion proportion of XMCCC (21 d) is stable at around 0.028%.On this basis,combined with characterization methods,the formation mechanism and the gas sealing mechanism of XM-CCM were explored.The results show that the active functional groups such as hydroxyl group and carboxyl group in XG chelate with Ca²⁺on the surface of slurry particles,and the clay particles are bound between the hydration products of cement particles,which improve the mechanical properties of XM-CCC.The hexagonal plate Mg(OH)² crystals generated by MgO hydration support the pores of the system,which improves the shrinkage resistance of XM-CCC.In terms of pore structure,XG changes the pore structure of XM-CCC and reduces the average pore diameter.When Mg(OH)² crystal fills the pores,the crystal growth pressure generated can resist the pore pressure,keep the matrix from cracking,and reduce the porosity at the same time.Under the combined action of XG and MgO,the gas permeability coefficient of XM-CCC is only 1.47×10^-12,which is much lower than that of surrounding rock.In economy of engineering application,XM-CCC has the advantages of convenient materials,simple production,low cost and simple and flexible construction technology.The field application results show that the XM-CCC coating is uniform,complete,and has good anti cracking and sealing properties,so it has a good application prospect.

1 试验材料与方法

   1.1 试验材料

   1.2 材料制备

   1.3 测试方法

2 结果与讨论

   2.1 CCC浆液性能分析

   2.2 MgO和XG对XM-CCC宏观性能的影响分析

   2.3 XM-CCC的表征和形成机理

   2.4 XM-CCC的堵漏风性能

3 XM-CCC的经济性与现场应用

   3.1 XM-CCC的经济性

   3.2 XM-CCC的现场应用

4 结论