【摘要】 在工程勘察中,水压致裂法是一种非常有效的原地应力测试方法,在隧道工程、水电工程等地下空间开发领域具有较为广泛的应用。该方法以线弹性理论为基础,通过水压驱动岩体破裂,在此过程中记录压力—时间曲线。通过该试验曲线可获得破裂压力、重张压力和闭合压力三个特征值,以此计算得到区域主应力值。其中,闭合压力的确定对于计算结果的准确性具有重要的影响。本文深入分析了水压致裂过程中的水—岩耦合特征,提出了利用瞬时流量突变来确定闭合压力的新方法。在此基础上,通过原位试验验证了这种新方法的有效性,并与目前常用的几种确定闭合压力的方法进行了对比分析。结果显示,该方法确定闭合压力具有较高的准确性,且符合水压致裂的实际物理过程。该研究对于提高水压致裂测试结果的准确性具有重要的意义。更多还原

【Abstract】 As an effective method for in-situ stress measurement, the hydraulic fracturing has a wide range of applications in the field of underground space development such as tunnel engineering and hydropower engineering. Based on the linear elasticity theory, the method forces rock to be cracked by water pressure, and records the pressure-time curve in this process. Through the testing curve, three characteristic values of break, reopening and shut-in pressures are obtained, and the regional principal stress value is calculated by using above values. Especially, the determination of the shut-in pressure has an important influence on the accuracy of the calculation result. Several methods for determining the shut-in pressure value are comprehensively analyzed in the paper, and combined with the basic characteristics of the hydraulic fracturing water-rock coupling process, a new method for determining the shut-in pressure by using instantaneous flow mutation is proposed. Moreover, the detailed comparison has been conducted between the new method and other existing methods. The results show that the new method has a good accuracy, and meets the physical process of hydraulic fracturing. This method is of great significance for improving the accuracy of the hydraulic fracturing test results.更多还原