冲击碾压模拟试验设备研制

冲击压路机已大量用于各种原位地基土以及填土的压实处理，压实深度明显大于传统压路机和平板压实设备。但冲击压路机在冲击碾压过程中的能量传递过程、土中应力和位移的分布情况等尚不清楚。为探讨冲击碾压加固地基的机制和加固效果的主要影响因素，研制了冲击碾压模拟试验设备。该设备主要由模型箱、模型冲击轮、简易缓冲装置以及支架与牵引系统四部分组成，其中核心组成部分是具有不同外接圆尺寸大小和质量的三边形模型冲击轮。模型冲击轮可通过牵引系统中电机的牵引作用，在试验土体表面沿直线滚动，对土体施加冲击碾压作用。采用该设备进行了不同尺寸的模型冲击轮冲击碾压砂土的模型试验，并采用直径为2.5 cm的小型静力触探仪对冲击碾压加固效果进行检测。结果表明：该试验设备可用于实现对非圆形冲击轮冲击压实土体过程的模拟，同时显示冲击轮尺寸对冲碾加固效果的影响与冲碾遍数有关，且该影响在不同深度的土体中会有不同的响应，增大冲击轮的尺寸可以在土体的浅层深度范围内获得更好的加固效果。

Development of a simulation device for impact roller

High-energy impact roller (IR) has been widely used to compact in-situ soils or fills for many kinds of earthworks. The IR applies high energy to the ground and densifies deeper soils than conventional rollers and plate-type compactors. But the transferring of IR energy into soil, the distributions of stress and displacement in soil while impacting and effect of the different masses and shapes of impact modules to the effectiveness of compaction are still unclear. This paper presents an impact roller simulation device to investigate the mechanism as well as the influencing factors on improvement of high-energy IR compaction. The device mainly consists of four parts including model box, model impact wheel, simplified buffering system and frame-towing system. The model impact wheels, as the key part of the device, are all 3-sided with different sizes and weights. The non-circular model impact wheels are towed with an electric motor through a steel rope and then roll on the surface of soil specimen, which is similar to the virtual process of IR compaction. Using this device, three laboratory compaction tests are carried out to verify the effectiveness of this device and investigate effects of impact wheel’s sizes on the effectiveness of IR compaction. A Chinese electric cone penetrometer of 2.5 cm in diameter is used to verify the effectiveness of IR compaction. The results of laboratory compaction tests show that the impact roller simulation device is suitable for modeling IR compaction and it is easy to operate. The cone penetration data indicate that the effects of impact wheel’s sizes on compaction are related to passes of IR compaction and that better effectiveness of IR compaction in shallow depth can be achieved by increasing the size of impact wheel.