红砂岩物理力学性质及其路基压实功研究

Study on physical and mechanical properties of red sandstone and its roadbed compaction work

为了研究红砂岩的工程性能及其路基压实功的变化规律,以浙南地区G60沪昆高速公路改扩建路基工程为例,首先开展了室内试验分析红砂岩的成分、崩解性和抗剪强度,然后通过现场压实试验分析压实遍数、速度、压实功与压实度之间的关系,最后对压实完成的红砂岩路基进行强度检测以验证全过程。结果表明:红砂岩的一次循环和二次循环耐崩解指数分别约为64.68%、13.71%,其耐崩解性属于最低等级,应用于路基填筑需要消解处理;当红砂岩消解破碎后粒径小于1.25 mm的颗粒占比达到95%以上时,便趋于稳定,不易继续崩解;崩解后形成的红砂土抗剪强度比一般土体高,其内摩擦角和黏聚力分别为31.95°、22.39 kPa;经过现场试验研究分析得到了在同一工况下压实功与压实度之间存在指数函数关系,因此在该工况下可通过压实功来判断路基的压实度。可见,将红砂岩应用于路基填筑工程并通过压实功初步判断路基压实度的方法是可行的,本技术方案可为后续路基工程压实度检测方面提供技术参考。

In order to study the engineering performance of red sandstone and the variation law of its roadbed compaction work,taking the G60 Shanghai-Kunming Expressway reconstruction and expansion roadbed project in southern Zhejiang as an example,the laboratory test was first conducted to analyze the composition,slaking and shear strength of red sandstone and then the field compaction test was performed to shed light on the relationship between the number of compaction times,speed,compaction work and compaction degree,and finally the strength test was carried out on the completed red sandstone roadbed to verify the whole process.The results show that slaking resistance indices of red sandstone in the primary cycle and the secondary cycle are about 64.68%and 13.71%respectively,with its slaking resistance rated within the lowest tier,which needs to be disintegrated when used in roadbed filling;when the percentage of particles with particle size less than 1.25 mm reaches more than 95%after slaking and crushing,it tends to be stabilized,unlikely to continue slaking;the shear strength of red sandstone formed after slaking is higher than that of general soil,with the internal friction angle and cohesion 31.95°and 22.39 kPa respectively;the analysis of field test derives an exponential function relationship between compaction work and compaction degree under the same working condition,under which the compaction degree of roadbed can be judged through the compaction work.Thus,it is feasible to apply red sandstone to roadbed filling projects and preliminarily judge the compaction degree of roadbed in light of the compaction work,which can provide a technical reference for the subsequent compaction degree testing of roadbed projects.