土体含水率和金属波纹状表面对界面黏附力影响

Experimental study on the influence of soil moisture content and metal corrugated surface on the interfacial adhesion

为解决盾构设备在穿越富水富黏地层时刀盘结泥饼的问题,开展金属刀盘仿生减黏研究。依据蜣螂、蚯蚓等土壤动物的非光滑波纹状体表具有较好的减黏特性,研究了波纹状金属表面与土体间的黏附关系。基于自行设计的黏附力拉拔试验装置,同时采用缠绕金属丝的方式实现测锥表面具有波纹形凸起效果,分析不同波纹凸起程度以及土体含水率变化对界面黏附特征的影响,测定土体与金属界面间的黏附力大小以及锥体表面黏土量。结果表明:黏附力大小与土体含水率的增长呈反比关系,土体含水率偏于塑限(w=24%)时黏附力趋于最大,随着土体含水率逐渐增加,黏附力逐渐减小。同时,在含水率较小和波峰凸起程度较小的试验条件下,波纹状测锥表面黏附土体较少,当土体含水率较低(w=24%,26%)时,光滑测锥与波峰高度0.1及0.2 mm测锥表面黏附的土体质量相近;当波峰高度逐渐增加时,锥体黏土量增加;而当含水率较高(w=30%)时,测锥表面的波纹状凸起则会加重土体黏附现象,波峰高度越高会造成测锥表面的黏附情况越严重。

In order to solve the problem of slurry cake formation on the cutter head when the shield machine traverses the water rich and clay rich stratum,a study on the bionic viscosity reduction of metal cutter head was carried out.On the basis of the non-smooth corrugated surface of soil animals such as dung beetles and earthworms,which have good viscosity reducing properties,the adhesion relationship between corrugated metal surface and soil was studied.Based on the self-designed adhesion pull test device,at the same time,the method of winding metal wire was used to achieve the corrugated convex effect on the surface of the measuring cone.The influence of different corrugated protrusion and the change of moisture content of soil on the adhesion characteristics of the interface was analyzed.The adhesion force between the soil and metal interface and the amount of clay on cone surface of the measuring cone were measured.The results showed that the adhesion force is inversely proportional to the increase of soil moisture content.When the soil moisture content is less than the plastic limit(w=24%),the adhesion force tends to be the largest.As the soil moisture content gradually increases,the adhesion force gradually decreases.At the same time,under the test conditions of small moisture content and the less corrugated convex,the corrugated cone surface has less adhered soil.When the moisture content of soil is low,such as w=24%,26%,the quality of soil adhered to the surface of the smooth measuring cone and the corrugated height of 0.1 and 0.2 mm is similar.When the corrugated height of measuring cone gradually increases,the clay content on the measuring cone increases,and when the moisture content of soil is higher(w=30%),the corrugated protrusion on the surface of measuring cone will increase the adhesion of the soil.The higher the corrugated height of the measuring cone,the more serious the adhesion of soil on the measuring cone.