土工格栅加筋泡沫轻质土抗折性能试验研究

李银河¹，刘勇^1*，张宏博²

1.山东交通学院交通土建工程学院，山东 济南  250357;2.山东大学齐鲁交通学院，山东 济南  250061

摘要：为研究土工格栅加筋泡沫轻质土的抗折性能，将水、水泥、发泡剂按一定质量比配备，满足流值为160~200 mm，采用4种不同的土工格栅加筋层数（0、1、2、3）和3种湿密度（600、700、800 kg/m³），将边长95 mm的正方形和宽95 mm、长395 mm的矩形土工格栅放入试模指定位置，养护28 d后脱模，制备土工格栅加筋泡沫轻质土试件，对其进行无侧限抗压强度试验和四点弯曲试验，从位移-荷载曲线、破坏形态、位移-荷载特征、无侧限抗压强度和抗折强度等方面分析湿密度和加筋层数对泡沫轻质土抗折性能的影响。试验结果发现：施载后土工格栅加筋泡沫轻质土由脆性破坏变为弹塑性破坏，根据黏结应力机制将荷载传递到试件内部，显著提高泡沫轻质土的抗折性能；在加载过程中，前期主要由泡沫轻质土承担荷载，后期主要由土工格栅承担荷载；加入土工格栅明显提高泡沫轻质土的无侧限抗压强度和抗折强度，最大无侧限抗压强度为3.16 MPa，抗折强度最大可提高168%；建立基于湿密度和加筋层数的无侧限抗压强度拟合方程，发现无侧限抗压强度与抗折强度之比与湿密度间相关性较好。

关键词：泡沫轻质土；土工格栅；抗折性能；位移-荷载曲线

Experimental study on the flexural performance of geogrid-reinforced foamed lightweight soil

LI Yinhe¹, LIU Yong^1*, ZHANG Hongbo²

1. School of Civil Engineering, Shandong Jiaotong University, Jinan 250357, China;

2. School of Qilu Transportation，Shandong University, Jinan 250061,China

Abstract: To study the flexural performance of geogrid-reinforced foam lightweight soil, water, cement, andfoaming agent are mixed in a certain mass ratio to achieve a flow value of 160-200 mm. Four different numbers of geogrid reinforcement layers (0, 1, 2, 3 layers) and three wet densities (600, 700, 800 kg/m³) are used. Square geogrids with a side length of 95 mm and rectangular geogrids measuring 95 mm in width and 395 mm in length are placed in the test mold. After curing for 28 days, the specimens are demolded, and foam lightweight soil specimens reinforced with geogrids are prepared. Unconfined compressive strength tests and four-point bending tests are conducted to analyze the effects of wet density and reinforcement layers on the flexural performance of foam lightweight soil from the aspects of displacement-load curves, failure modes, displacement-load characteristics, unconfined compressive strength, and flexural strength. The research findings are as follows: after loading, the reinforced foam lightweight soil transitions from brittle failure to elastic-plastic failure, significantly enhancing the flexural performance of the foam lightweight soil by transmitting load to the interior of the specimen according to the bonding stress mechanism; during the loading process, the foam lightweight soil primarily bear the load in the early stage, while the geogrid mainly bear the load in the later stage; the addition of geogrids significantly improves both the unconfined compressive strength and flexural strength of foam lightweight soil, with the maximum unconfined compressive strength reaching 3.16 MPa and the flexural strength increasing by up to 168%; a predictive equation for unconfined compressive strength based on wet density and reinforcement layers is established, revealing a good correlation between the ratio of unconfined compressive strength to flexural strength and wet density.

Keywords: foam lightweight soil; geogrid; flexural performance; displacement-load curve