摘要
注浆加固后岩体静、动态力学响应是岩石工程安全与稳定性评估的重要指标,为研究静态和循环冲击荷载下注浆加固岩石的力学特性,利用落锤冲击试验装置,对不同注浆类型的红砂岩试样进行破坏机制与损伤演化模型研究,试验结果表明:(1)水泥注浆材料由于其黏结性能及本身强度较低,不能很好的起到加固效果,树脂注浆材料能够有效改善裂缝造成的应力集中,树脂由于强度高、韧性以及与基体的协调性好,具有良好的加固效果;(2)水泥注浆体中间位置的最大拉应变随着时间的增加而迅速增大,并在荷载达到水泥开裂的峰值荷载时发生突变,对于树脂加固后的试样,应变变化较为平顺,无明显突变;(3)当冲击能量较大时,无论何种类型的加固试样,均在一次冲击下就发生破坏,树脂注浆试样和完整试样,其冲击能量与冲击寿命呈双对数线性关系,当冲击累积残余应变达到静动态峰值应变差时,试样发生破坏;(4)基于冲击累积残余应变定义损伤量,得到循环冲击损伤演化曲线,损伤演化呈明显的三阶段变化,通过不同注浆类型、不同冲击能量的试验验证,该演化模型能较好地模拟冲击损伤过程。
The static and dynamic mechanical responses of rock mass after grouting reinforcement are important for evaluating the safety and stability of rock engineering.In order to study the mechanical characteristics of grouting-reinforced rock under static and cyclic impact loads,the failure mechanism and damage evolution model of red sandstone samples of different grouting types were studied using the drop hammer impact test device.The test results show that specimens grouted by cement show poor reinforcement effect due to the low bonding performance and strength of the cement,while that resin grouting material can effectively improve the stress concentration caused by cracks and obtain a good reinforcement effect due to its high strength,toughness and good coordination with the rock.The maximum tension strain at the middle position of the cement grouting sample first increases rapidly and suddenly changes when the load reaches the peak value of the cement cracking load,while the strain changes of the specimens grouted by resin are smooth and there is no obvious mutation.All specimens,whether or not they are grouted,will be destroyed immediately when the impact energy is large enough.For both resin grouting specimens and un-cracked specimens,there is a clear double logarithmic linear relationship between the impact energy and the impact life,and the specimen will be damaged when the impact cumulative residual strain reaches the difference between the static peak strain and the dynamic peak strain.The damage evolution curve presenting an obvious three-stage change was obtained and verified by experiments of different grouting types and different impact energy.The damage evolution can better simulate the damage accumulation during the impact process.
作者
王志
秦文静
张丽娟
WANG Zhi;QIN Wenjing;ZHANG Lijuan(School of Mechanics and Safety Engineering,Zhengzhou University,Zhengzhou,Henan 450001,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2020年第12期2451-2459,共9页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金青年基金资助项目(51808509,51404212)。
关键词
岩石力学
注浆加固
循环冲击
破坏机制
损伤
应变
rock mechanics
grouting reinforcement
cyclic impact loading
failure mechanism
damage
strain
