作者：朱大鹏, 彭泰鑫, 黄玲

作者单位：西南石油大学地球科学与技术学院，四川 成都 610500

关键词：落石;缓冲效应;缩尺试验;砂土;垫层

摘要：

为得到科学的棚洞砂土垫层厚度，提高棚洞的安全性，进行0.5 m、1.0 m、1.5 m高度释放的3 kg、5 kg、7.26 kg落石冲击砂土缩尺试验，监测不同埋深的应力，对比分析不同垫层厚度、落石尺寸和高度的落石冲击效应。高度和落石尺寸一定，如从1.5 m高度释放的7.26 kg落石，在0.05 m、0.1 m、0.15 m的垫层厚度下，垫层下最大应力分别为1.51 MPa、3.20 MPa、1.19 MPa；落石高度和垫层厚度一定，如从1.5 m释放落石且垫层厚度为0.05 m时，3 kg落石和5 kg落石所对应的垫层下最大应力，分别约为1.15 MPa和1.18 MPa；落石尺寸和垫层厚度一定，如在垫层为0.1 m的情况下，7.26 kg落石从0.5 m、1.0 m和1.5 m释放，分别对应的土中最大应力为1.13 MPa、1.73 MPa和3.20 MPa。随着落石尺寸的增大和释放高度的增加，砂土中应力增大，且增速变快。一定厚度的砂土垫层对落石具有较好的缓冲作用，当厚度再增加，缓冲效果没有明显增强。在实际工程中，可根据棚洞强度、落石高度和落石尺寸来确定砂土垫层厚度。

Experimental study on layering effect of sand layer
ZHU Dapeng, PENG Taixin, HUANG Ling
School of Earth Sciences and Technology, Southwest Petroleum University, Chengdu 610500, China
Abstract: In order to obtain the thickness of the scientific shed tunnel sand layer and improve the safety of the shed tunnel. The 3 kg, 5 kg, and 7.26 kg rockfall impact sand scale tests were carried out at 0.5 m, 1.0 m, and 1.5 m height to monitor the stresses at different depths. The impact effects of different layer thicknesses, falling rock sizes and height were compared and analyzed. As a result, fix the height and falling rock size, such as 7.26 kg of falling rock released from a height of 1.5 m. Under the thickness of the layer of 0.05 m, 0.1 m, and 0.15 m, the maximum stress under the layer is 1.51 MPa, 3.20 MPa and 1.19 MPa respectively; fix the height of the falling rock and the thickness of the layer, when the falling rock is released from 1.5 m and the thickness of the layer is 0.05 m, the maximum stress under the layer corresponding to 3 kg of falling rock and 5 kg of falling rock is about 1.15 MPa and 1.18 MPa respectively; fix the layer thickness, when the mat layer is 0.1 m, 7.26 kg of falling rock is released from 0.5 m, 1.0 m and 1.5 m, and the corresponding maximum stresses in the soil are 1.13 MPa, 1.73 MPa and 3.20 MPa respectively. In conclusion, with the increase of the size of the falling rock and the increase of the release height, the stress in the sand increases and the growth rate becomes faster. A certain thickness of the sand layer has a good layering effect on the falling rock, and when the thickness is increased. The layering effect is not significantly enhanced. In actual engineering, the thickness of the sand layer can be determined according to the strength of the shed, the height of the falling rock and the size of the falling rock.
Keywords: rockfall;layering effect;scale test;sand;layer
2020, 46(3):44-51  收稿日期: 2019-08-20;收到修改稿日期: 2019-10-16
基金项目: 国家级大学生创新创业训练计划项目（201710615027，201810615039）
作者简介: 朱大鹏(1969-),男,湖北武汉市人,副教授,博士,研究方向为岩土与地质工程
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