基于MMLS3设备的土工布防治反射裂缝效果研究

MMLS3-Based Research on Anti-Reflective Cracking Performance of Geotextile

应用MMLS3设备对1/3比例路面结构模型进行加速加载试验,模拟车辆荷载造成的弯拉-剪切复合作用,并进行应变和裂缝扩展情况的跟踪监测,研究在面层和基层层间铺设土工布防治反射裂缝的效果.结果表明:有布组在面层初裂和裂缝贯穿时所对应的加载次数分别为无布组的3.55倍和3.25倍.初裂前,土工布由于削弱层间黏结,使面层层底总应变和弹性应变大于无布组,但可通过提高与沥青层结合后的复合断裂能延缓面层开裂;初裂后,土工布逐渐拉伸而承受更大拉伸力,协助面层抵抗弯拉和剪切作用,使得有布组总应变、弹性应变逐渐减小;贯穿后,土工布仍可保持裂缝两侧结构的联结,抑制裂缝加宽和结构错动,使得总应变和弹性应变稳定在180×10-6和9×10-6,而无布组由于裂缝继续加宽,总应变和弹性应变超过600×10-6和8×10-6并持续增长.

An accelerated pavement test using 1/3 model mobile load simulator（MMLS3） on a 1/3 proportional pavement structure model has been conducted to study the antireflective cracking performance of geotextile under the combination of tensile and shear effect due to traffic load.The strain and crack propagation has been monitored during the test.Results show that：for geotextile group,the load cycles of crack initiation and penetration are 3.55 and 3.25 times as much as non-geotextile group,respectively.The total strain and elastic strain of geotextile group are higher than nongeotextile group before crack initiation because of the reduction of interlayer adhesion.However,geotextile can help retard crack initiation by increasing the composite fracture energy combined with surface layer;after cracking,geotextile assists surface layer to endure the tensile and shear effect under traffic load with its increasing tensile deformation and tensile resistance,so the total strain and elastic strain of geotextile group decrease;after crack penetration,geotextile suppresses the horizontal propagation of the crack and the vertical displacement of the pavement structure by maintaining the connection of structure across the crack.Therefore,the total strain and elastic strain of geotextile group remain stable at 180×10^-6 and 9×10^-6 respectively.By contrast,the total strain and elastic strain of non-geotextile group exceed600×10^-6 and8×10^-6 respectively and continue to grow with the expansion of crack.