在寒区岩体中，由于非光滑节理面的切割作用，岩体内部常出现各种粗糙裂隙和缺陷，这些裂隙在冻融作用下对岩体工程构成潜在威胁。工程中常采用注浆技术加固裂隙岩体，但寒区特有的季节性变化和昼夜温差，导致注浆裂隙岩体仍面临冻融的影响，进而增加地质灾害的风险。因此，本文采用JRC量化裂隙粗糙度，通过单因素对比试验和正交试验设计，系统分析了冻融次数、裂隙倾角、粗糙度、注浆材料及围压等因素对岩体力学特性的影响，并重点探讨了这些因素之间的交互作用及协同效应，建立了考虑交互作用的多项式回归模型，揭示了复杂环境下岩体力学性能的交互机制。结合数值模拟验证了交互回归模型的合理性与可靠性，将模拟结果与试验结果对比，揭示了注浆裂隙砂岩的裂纹扩展规律和破坏机理。主要研究内容如下：

（1）因素独立作用下砂岩峰值应力影响程度排序：围压＞裂隙倾角＞注浆材料＞冻融循环次数＞粗糙度；弹性模量影响程度排序：冻融循环次数＞围压＞注浆材料＞裂隙倾角＞粗糙度。冻融循环通过水冰相变生成冻胀力，导致微裂隙扩展和孔隙结构劣化，表现为弱化作用。注浆材料通过提高岩样的粘结力和支撑能力、粗糙度通过增强浆液的锚固效果、裂隙倾角通过改善应力传递效率、围压通过提高岩样的致密性和限制变形，均表现为强化作用。

（2）通过交互作用分析，发现岩样的峰值应力与弹性模量呈现三种交互机制：交互增强机制，即相关因素均处于高水平时，峰值应力或弹性模量显著提升，体现为协同强化效应。交互抑制机制，即相关因素均处于高水平时，因素之间相互抑制彼此的强化或弱化作用。交互反转机制，即在不同条件下，某些因素的影响趋势发生逆转。具体而言，峰值应力的交互增强机制体现在注浆材料与粗糙度、注浆材料与围压、裂隙倾角与粗糙度的交互中；交互抑制机制则出现在注浆材料与冻融循环、围压与冻融循环的交互中。对于弹性模量，交互增强机制体现在裂隙倾角与围压、注浆材料与粗糙度、围压与粗糙度的交互中；交互反转机制则出现在冻融循环与裂隙倾角的交互中。

（3）采用FDEM数值模拟手段，进一步分析了试验中难以观测的岩样应力演化过程和破裂模式。结果表明：将交互回归模型计算的弹性模量作为输入参数时，能够提高注浆裂隙岩体在数值模拟中力学预测的精度，并揭示了单一因素对砂岩应力演化规律的影响。将模拟结果与室内试验结果进行对比，发现交互增强机制能有效抑制裂纹扩展，降低岩样的破坏程度；交互抑制机制能在一定程度上抑制微裂隙的扩展，但无法修复冻融过程中造成的内部累积损伤，导致岩样整体破坏程度加剧。

In cold-region rock masses, various rough fractures and defects often appear inside the rock mass due to the cutting effect of non-smooth joint surfaces. These fractures pose a potential threat to rock engineering under freeze-thaw action. Grouting technology is often used in engineering to reinforce fractured rock masses, but the seasonal changes and diurnal temperature differences unique to cold regions cause grouted fractured rock masses to still face the impact of freeze-thaw, which in turn increases the risk of geological disasters. Therefore, this paper uses JRC to quantify the roughness of the cracks. Through single-factor comparative experiments and orthogonal test designs, the paper systematically analyzes the effects of factors such as the number of freeze-thaw cycles, crack dip angle, roughness, grouting material, and confining pressure on the mechanical properties of the rock. The paper also focuses on the interactions and synergistic effects between these factors, establishes a polynomial regression model that considers interactions, and reveals the interaction mechanism of the mechanical properties of rock in complex environments. The rationality and reliability of the interactive regression model were verified by combining numerical simulation. The simulation results were compared with the experimental results to reveal the crack propagation law and failure mechanism of grouted fractured sandstone. The main research contents are as follows:

(1) Ranking the degree of influence of peak stress on sandstone under the independent action of factors: confining pressure > fracture dip angle > grouting material > number of freeze-thaw cycles > roughness; ranking the degree of influence of elastic modulus: number of freeze-thaw cycles > confining pressure > grouting material > fracture dip angle > roughness. Freeze-thaw cycles generate frost heave forces through the phase change of water ice, which leads to the expansion of micro-fractures and the deterioration of the pore structure, which is expressed as a weakening effect. Grouting materials strengthen the rock sample by improving its bonding and supporting capacity, roughness strengthens the anchoring effect of the grout, the angle of the cracks improves the efficiency of stress transmission, and confining pressure improves the compactness of the rock sample and limits deformation.

(2) Through interaction analysis, it was found that the peak stress and elastic modulus of the rock sample showed three interaction mechanisms: the interactive enhancement mechanism, that is, when the relevant factors are at a high level, the peak stress or elastic modulus is significantly enhanced, which is reflected as a synergistic strengthening effect. The interactive inhibition mechanism, that is, when the relevant factors are at a high level, the factors inhibit each other's strengthening or weakening effect. The interactive reversal mechanism, that is, under different conditions, the influence trend of some factors reverses. Specifically, the interactive enhancement mechanism of peak stress is reflected in the interaction between grouting material and roughness, grouting material and confining pressure, and fracture inclination angle and roughness; the interactive suppression mechanism occurs in the interaction between grouting material and freeze-thaw cycles, and confining pressure and freeze-thaw cycles. For the elastic modulus, the interactive enhancement mechanism is reflected in the interaction of the crack dip angle and confining pressure, the grouting material and roughness, and the confining pressure and roughness; the interactive reversal mechanism appears in the interaction of the freeze-thaw cycle and the crack dip angle.

(3) FDEM numerical simulation was used to further analyze the stress evolution process and fracture mode of the rock sample, which was difficult to observe in the experiment. The results show that using the elastic modulus calculated by the interactive regression model as the input parameter can improve the accuracy of the mechanical prediction of the grouted fractured rock mass in numerical simulation, and reveal the influence of a single factor on the stress evolution law of sandstone. Comparing the simulation results with the results of the indoor tests, it was found that the interactive enhancement mechanism can effectively inhibit crack propagation and reduce the degree of damage to the rock sample. The interactive inhibition mechanism can inhibit the expansion of micro-cracks to a certain extent, but it cannot repair the internal cumulative damage caused by the freeze-thaw process, which leads to an increase in the overall degree of damage to the rock sample.