实验技术与管理

随着我国基础设施建设重心的战略西移，西部山区已成为大型隧道及地下工程建设的核心。然而，该区域地质构造错综复杂，且常伴有丰富的地下水赋存条件，导致地下工程普遍面临水害威胁。不同岩性的岩石在水害发生过程中表现显著差异，泥质板岩受水影响尤为突出，其渐进破坏力学特性与损伤规律亟待系统研究。为此，针对不同含水状态泥质板岩开展了单轴压缩试验和全过程同步声发射测试，揭示了泥质板岩力学响应特性与声发射时空演化规律，总结了不同含水状态泥质板岩破坏过程的差异性规律。结果表明：（1）力学试验显示泥质板岩试样的抗压强度由干燥状态的62.7 MPa降为饱水状态的34.25 MPa，降低了45.37%，弹性模量由干燥状态的12.29 GPa降低为饱水状态的9.35 GPa，降低了23.9%。（2）泥质板岩在失稳前会发生局部多次破裂，导致环向应变多次突增，通过量化环向应变速率与轴向应变速率关系，当环向应变速率达到轴向应变速率的10倍时，将其视为失稳前兆，且水的存在导致试样裂纹出现失稳扩展的时间提前。（3）饱水状态泥质板岩的累计振铃计数和累计能量相较干燥状态分别降低了25%和84.6%，且水的存在会导致振铃计数和能量的“突增”现象在时序上发生滞后。（4）局部破裂的发生伴随着主频的降低和幅值的上升，低频-高幅信号数量的增多可作为不同含水状态泥质板岩失稳破坏的前兆信息，通过AF-RA法分析可知水的存在会削弱由板理控制的张拉破坏模式。上述研究结论对类似地质条件下的岩体工程具有重要的理论指导与实践参考意义。

[Objective] With the strategic westward shift of China’s infrastructure development， the western mountainous regions have become the focal point for large-scale tunnel and underground engineering construction. However， these regions are characterized by highly complex geological structures and abundant groundwater reserves， exposing underground projects to water-induced hazards. Rocks of different lithologies exhibit noticeable behavioral differences under water-induced degradation. Argillaceous slate is particularly susceptible to water; thus， its progressive failure mechanical properties and damage evolution laws urgently require systematic investigation. To address this， uniaxial compression tests coupled with synchronous full-process acoustic emission (AE) monitoring were conducted on argillaceous slate specimens under varying water-bearing states. This study reveals the mechanical response characteristics and spatiotemporal evolution laws of AE in argillaceous slate， summarizing the distinctive patterns in rock failure processes across different water-bearing conditions. [Results] (1) The compressive strength of the argillaceous slate specimens decreased from 62.7 MPa in the dry state to 34.25 MPa in the water-saturated state， representing a reduction of 45.37%. Similarly， the elastic modulus declined from 12.29 GPa in the dry state to 9.35 GPa in the saturated state， corresponding to a decrease of 23.9%. (2) Following water saturation， the crack damage stress level of the argillaceous slate specimens decreased by 15%. Compared with the dry state， the elastic strain energy of the specimens in the water-saturated state dropped significantly by 67%. (3) The cumulative AE ring-down count of the specimens decreased from 1.6 × 10⁴ in the dry state to 1.2 × 10⁴ in the saturated state， representing a 25% reduction. The cumulative AE energy plummeted from 142.76 × 10^–18 J in the dry state to 22.01 × 10^–18 J in the saturated state， amounting to an 84.6% decrease. (4) For the specimens in the dry state， the dominant frequency exhibited notable sudden drops around 200 and 400 s of loading. Meanwhile， after 300 s， the dominant frequency signals of the specimens in the water-saturated state were relatively evenly distributed within the 100–400 kHz frequency band. The proportion of low-amplitude signals for both states accounted for approximately 80%. Additionally， compared with the dry state， AE events during the initial loading stage were extremely sparse for the specimens in the water-saturated state. The tensile-shear microcracking mechanism of the argillaceous slate specimens was primarily characterized by a combination of high AF values and low RA values. The RA values of the saturated specimens exhibited significant increases in quantity and absolute magnitude. [Conclusions] (1) Argillaceous slate specimens undergo multiple localized fracturing during the yield stage. Such phased sudden increases in circumferential strain act as a key precursor to the macroscopic failure of the rock. Quantitatively， the instability precursor is defined as the point at which the circumferential strain rate reaches 10 times the axial strain rate. (2) Water saturation significantly weakens the localized multiple fracturing phenomenon and its associated failure precursors in argillaceous slate. Consequently， the failure process lacks the large-scale， abrupt damage observed in the dry state. (3) AE signal characteristics further reveal the weakening and transitional mechanisms induced by water on the failure mode of argillaceous slate. Unlike specimens in the dry state， which exhibited sudden drops in the AE’s b-value and dominant frequency due to internal crack activation， specimens in the water-saturated state displayed a more uniform dominant frequency distribution， indicating a more gradual and stable overall failure process. (4) The significantly increase in RA values in the water-saturated state indicates an alteration in the microcracking mode induced by water， which further suppresses the abrupt propagation of localized tensile cracks and leads to a more ductile instability and failure behavior.