2015年12月25日山东平邑塌陷事件产生的位移场与应力场

发布时间：2018-10-26 11:54

【摘要】：2015年12月25日山东平邑县发生石膏矿塌陷事件。采用各向同性塌缩点源模型计算了该塌陷事件在周围地表产生的位移场、水平应力场及在其附近的蒙山山前断裂上的库伦破裂应力变化。结果表明:1)塌陷中心的水平位移达18mm,在距离塌陷位置约5km范围内的水平位移1mm,方向指向塌陷中心;塌陷中心的垂直沉降达4mm,在塌陷中心约3km以内沉降1mm,水平位移和垂直位移在远处快速衰减到可以忽略不计,这是由于该塌陷源较浅,位移变化局限在地表局部所致。2)由于自由表面的影响,该塌陷造成地下2km深度的约5km范围内呈现面收缩应力状态,面收缩应力达1 000Pa;而在远处均处于面膨胀应力状态,膨胀应力最大约达1 000Pa,面膨胀应力在距塌陷中心约10km处迅速衰减到100Pa以下。在2km深度的平面上造成的最大主张应力和主压应力达10 000Pa,在主压应力大于主张应力的塌陷中心约5km范围内,主压应力呈现以塌陷为中心的径向分布,在距塌陷中心约5km以外,主张应力呈现以塌陷为中心的径向分布,随着距离的增大,主压应力和主张应力快速衰减到100Pa量级。3)该塌陷造成了其西北部的蒙山山前断裂(被认为不活动的断层段)上的库伦破裂应力降低,最大值达2 500Pa,造成了东南部的蒙山山前断裂(被认为第四纪左旋正断活动的断层段)上的库伦破裂应力增加,最大值达2 400Pa,在分析该断裂的危险性时要予以注意。
[Abstract]:On December 25, 2015, gypsum mine collapsed in Pingyi County, Shandong Province. The isotropic collapse point source model is used to calculate the displacement field, horizontal stress field and Coulomb stress change on the nearby Mengshan Foreland fault. The results show that: 1) the horizontal displacement of the collapse center is 18 mm, and the horizontal displacement within the range of 5km is about 1 mm, pointing to the collapse center; The vertical subsidence of the collapse center is up to 4 mm, and within about 3km of the collapse center, the horizontal displacement and vertical displacement decrease rapidly to negligible in the distance, which is due to the shallow source of the collapse. The displacement change is limited to the local surface. 2) due to the influence of the free surface, the collapse causes the surface shrinkage stress in the 5km range of the underground 2km depth, and the surface shrinkage stress reaches 1 000 Pa. In the distance, all of them are in the state of surface expansion stress, and the maximum expansion stress is about 1 000 Pa.The surface expansion stress decreases rapidly to below 100Pa at the point about 10km from the center of the collapse. The maximum claimed stress and principal compressive stress on the plane of 2km depth are up to 10 000 Pa.The principal compressive stress shows a radial distribution centered on the collapse in the range of about 5km in which the principal compressive stress is larger than the dominant stress, and outside the collapse center about 5km. The stress is distributed in radial direction with collapse as the center, and increases with the increase of distance. The main compressive stress and the claim stress rapidly attenuate to the 100Pa order of magnitude. 3) the collapse resulted in a decrease in the Coulomb rupture stress on the Mengshan Foreland fault (the fault segment considered inactive) in the northwestern part of the country, with a maximum value of 2 500 Pa. The Coulomb fracture stress on the Mengshan Foreland fault (considered to be the active fault segment of the Quaternary left-lateral normal fault) in the southeast of China is increased to a maximum of 2 400 Pa. the risk of the fault should be paid attention to.
【作者单位】：防灾科技学院;山东省地震局;
【基金】：国家自然科学基金(41674055) 河北省地震科技星火计划(DZ20170109001)共同资助
【分类号】：P315.727

【相似文献】