岫岩陨石撞击坑的速度结构和抗震性能分析

岫岩陨石撞击坑位于辽东半岛北部低山丘陵地区,直径1.8km,保存完好。由于陨石的撞击和此后的沉积作用在坑内形成了特殊的地貌、地质和地球物理环境,使坑内与坑外的介质在速度方面存在差异,尤其是湖相沉积的软弱淤泥层使得坑底上建造的房屋就像躺在一张巨大的海绵垫上一样,使人们常常感到有微震发生,表明坑底的软弱地层对地面的震动产生了放大作用,严重地影响了地基的稳定性,从而影响到地面建筑物的抗震性能。本文采用高分辨折射探测方法,获得了陨石坑内的速度结构和软弱地层的分布,分析了陨石坑地基的抗震性能,为坑内地基和地面建筑物的地震危险性评价提供了可靠的基础资料。

Analysis on the Velocity Structure and Seismic Performance of Xiuyan Impact Crater

The Xiuyan impact crater with a diameter of 1.8km is located at northern hills of the Liaodong peninsula, Liaoning province, China and reserved well. A special geomorphological, geological and geophysical environment after the meteorite impact and subsequent deposit at the crater makes different in medium velocity between inside and outside the crater. Especially the soft mud from lacustrine deposits makes the buildings built at the bottom like lying on a huge sponge pad, that often makes people feel the micro earthquakes occurred, which suggests that the soft stratum on the bottom has played an amplification role in the vibration of the ground and seriously affects the stability of the foundation and the seismic performance of the buildings on the ground. In the project, the velocity structure and the distribution of weak stratum in the crater are obtained by using high resolution refraction detection method, and the seismic performance of the foundation of the crater is analyzed in order to provide reliable basic data for the evaluation of seismic risk of pit foundation and ground buildings.