小相似比高位滑坡模型试验相似材料研究

Research on similar materials of high-elevation landslide model test withsmall similarity ratio

相似材料的选取和配制是成功模拟原型斜坡的关键。对于坡高几百米甚至上千米的高位滑坡,由于试验条件的限制,在进行物理模拟试验时常常需要采取小相似比(1∶100~1∶1 000)并配制出强度较低的相似材料,而现有的相似材料强度往往偏大,难以满足试验要求。以四川省茂县松坪沟沟口坡高500 m的顺层岩质斜坡为原型,设计了几何相似比为1∶200的振动台模型试验,并采用正交试验法设计了16组配比试样,以(铁粉+重晶石粉)/骨料、铁粉/(铁粉+重晶石粉)、石膏/混合料、水/混合料、甘油/混合料质量比为5种因素,每种因素设置4个水平,通过室内试验测试出每组试样的物理力学参数。结果表明:所配制材料的力学参数变化区间较大,能满足小相似比、高密度、高内摩擦角和低强度相似模型试验的需求;相似材料黏聚力随重晶石粉和铁粉含量的增加呈现先减小后增大的趋势;内摩擦角随石英含量的增加而先增加后减小;弹性模量随重晶石粉和铁粉含量的增加而先增大后减小。试验结果对类似小相似比模型试验材料的配制具有参考意义。

The selection and preparation of similar materials is a key to successfully simulate prototype slopes.For high-elevation landslides with a slope height of several hundred meters or even thousands of meters,due to the limitation of test conditions,it is necessary to adopt a small similarity ratio(1∶100~1∶1000)and prepare similar materials with lower strength in physical simulation tests.However,the strength of existing similar materials is often too large to meet the test requirements.A vibration platform model test with a geometric similarity ratio of 1∶200 was designed based on the 500 m high bedding rock slope at the Songpinggou gully in Maoxian County,Sichuan Province,and 16 groups of ratio samples were designed by orthogonal test method.In the orthogonal test,iron powder/aggregate,iron powder/(iron powder+barite powder),gypsum/mixture,water/mixture,glycerol/mixture were selected as five factors,each factor set four levels,and the physical and mechanical parameters of each group of samples were tested through laboratory tests.The results showed that the mechanical parameters of the prepared materials changed in a large range,which could meet the model test needs of small similarity ratio,high density,high internal friction angle and low strength similarity.The cohesion of similar materials decreased first and then increased with the increase of barite powder and iron powder content,the internal friction angle increased first and then decreased with the increase of quartz content,while the elastic modulus increased first and then decreased with the increase of barite powder and iron powder content.The test results have reference significance for the materials preparation of similar small similarity ratio model test.