陕北地区毛乌素沙漠公路风积沙工程特性研究

Research on engineering characteristics of aeolian sand in desert region of Maowusu in northern Shaanxi

文章通过筛分试验、重型标准击实试验、直剪试验、室内回弹试验、CBR试验等方法分析了3种沙样的击实特性与强度特性。试验结果表明：陕北地区风积沙颗粒较均匀，级配差，粒径分布在0．6～0．074mm之间，属于特细沙；击实试验曲线呈横写的S型，即风积沙在干燥状态和最优含水率下均可被压实；3种沙样的不均匀系数Cu3〉Cu2〉Cu1，而内摩擦角φs〉φ2〉φ1，回弹模量E03〉E02〉E01；风积沙的室内回弹模量在45-70MPa之间变化，不浸水的CBPmax值比浸水4d的CBRmax值高出近2倍。通过控制机械参数（振幅A=0．4mm，频率f=48Hz），现场压实风积沙路基在压实5遍时，压实度可达到96．4％，CBRmax值可达到。24．2，均能满足相关规范要求。

This paper studied three kinds of aeolian sand samples, with respect to compaction characteristics and strength characteristics by using different test methods, i.e. screening tests, heavy typical compacting test, direct shear test, indoor rebound test and CBR test. The results showed that the gradation of aeolian sand in northern Shaanxi was bad, with particle size ranging from 0. 6 mm to 0. 074 mm. The compaction curve was plotted similar to a horizontaUy-written letter S, indicating that the aeolian sand could be well compacted whatever it was dry or wet. The results of nonuniformity coefficient of three samples are in the order Cu3 Cu2〉Cu1, for the internal friction angle, φ3〉φ2〉φ1, and for the resilient modulus, E03S〉E02〉E01. Resilient modulus ranged from 45 MPa to 70 MPa. With the increasing degree of compaction, CBR value increased significantly.＇ The CBR value of aeolian sand flooding with 4 d is double lower than that of not flooding. Field compaction tests were carried out as the amplitude A of the machine was 0. 4 mm and the frequency f was 48 Ha When the roadbed was compacted five times, the degree of compaction was 96. 4% and the value of CBRmax was 24. 2, which are quite acceptable.