盐下临界角库伦楔在库车坳陷克拉苏构造带的应用及模拟实验

发布时间：2018-05-31 22:52

本文选题：库车坳陷 + 临界角库伦楔公式　；参考：《南京大学》2017年硕士论文

【摘要】：临界角库伦楔模型的建立,确定了楔状体坡度与楔状体和底部滑脱层的岩石力学性质之间的关系。由公式可得,底面滑脱层的内摩擦系数越大,楔状体的坡度越大;而岩层的内摩擦系数越大,楔状体的坡度越小。但对于库车坳陷克拉苏构造带盐下发育的褶皱冲断带楔状体,由于有上层盐岩的重量对楔状体的压力,运用传统的临界角库伦楔公式计算得到的结果与实际不符。本文考虑了上层盐岩的重量,推导出了适用于盐下楔状体的临界角库伦楔公式。根据重新推导后的临界角库伦楔公式对库车坳陷底部滑脱层的性质进行了计算,得出底部滑脱层内摩擦角为13.4°～18.1°。推测该滑脱层的性质与泥岩或碳质页岩的性质相符,该滑脱层可能为中三叠统或上三叠统的泥岩或碳质页岩。由重新推导后得出的适用于盐下楔状体的临界角库伦楔公式和库车坳陷克拉苏构造带大北段地震解释结果可以得出,越靠近褶皱冲断带楔状体的前锋的部分,岩层所处的压力越大,楔状体的顶面坡度越大。为了验证这一结论,设计了一组离散元数值模拟实验,实验的结果表明,越靠近楔状体前锋的顶面坡度越大,而越靠近楔状体后端,楔状体的顶面坡度越小。这种现象与临界角库伦楔公式和库车坳陷克拉苏构造带所反应的特点一致。挤压端出现了一个反冲断层,各个逆冲断层之间位置间隔距离比较远。分析这些现象的原因可能都是因为上覆盐岩的压力造成的。物理模拟的结果也出现类似的现象,推测膏盐层的存在在纵向上的压力会使地层向下旋转,而在横向上由于膏盐层沿着楔状体顶面向前流动,又会使推覆体在向前逆冲时受到阻力。
[Abstract]:With the establishment of the critical angle Coulomb model, the relationship between the slope of the wedge and the rock mechanical properties of the wedge and the bottom slippage is determined. According to the formula, the greater the internal friction coefficient of the bottom slip layer, the bigger the slope of the wedge-like body, while the larger the internal friction coefficient of the rock layer, the smaller the slope of the wedge-like body. However, for the wedge-shaped fold thrust belt developed under salt in the Klassou structural belt of Kuqa depression, due to the pressure of the weight of the upper salt rock on the wedge body, the results obtained by using the traditional Coulomb wedge formula of critical angle are not consistent with the actual situation. In this paper, the critical angle Coulomb wedge formula suitable for wedge body under salt is derived by considering the weight of upper salt rock. The properties of the slip layer at the bottom of the Kuqa depression are calculated according to the re-derived critical angle Coulomb wedge formula. The internal friction angle of the bottom slip layer is 13.4 掳/ 18.1 掳. It is inferred that the nature of the detachment is consistent with that of mudstone or carbonaceous shale, and the detachment may be mudstone or carbonaceous shale of middle Triassic or upper Triassic. The critical angle Coulomb wedge formula for subsalt wedges and seismic interpretation results of the Klassou tectonic belt in Kuqa depression can be obtained from the derivation of the critical angle Coulomb wedge formula and the seismic interpretation results show that it is closer to the front part of the wedge body in the fold-thrust belt. The greater the pressure, the greater the top slope of the wedge. In order to verify this conclusion, a group of discrete element numerical simulation experiments are designed. The experimental results show that the more close to the front of the wedge, the bigger the slope of the top surface, and the smaller the slope of the top surface of the wedge is the closer it is to the back end of the wedge. This phenomenon is consistent with the characteristics of the critical angle Coulomb wedge formula and the Klassou tectonic belt in Kuqa depression. A recoil fault appeared at the extrusion end, and the distance between the thrust faults was relatively long. The analysis of these phenomena may be due to the pressure of the overlying salt rock. A similar phenomenon appears in the physical simulation. It is assumed that the vertical pressure of the gypsum salt layer will cause the formation to rotate downwards, and laterally because the gypsum salt layer flows forward along the top surface of the wedge body, In turn, the nappe will be subjected to resistance in the forward thrust.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P548

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