不同锚固方式下软弱破碎岩质边坡渐进破坏特性的模型试验研究

在软弱破碎岩体中进行人工边坡开挖，往往因局部坡体应力集中或变形过大而导致边坡失稳破坏，为此需要采用大量的锚杆加固岩体。为进一步了解该类边坡的变形破坏机制及其支护加固效果，以 Ⅳ 类围岩为参照对象，将其等效为单一均质地层，并根据相似理论建立其地质力学模型，随后开展了不同锚杆加固方式下岩质边坡破坏特性的试验研究。试验结果表明，当不采取加固措施时，软弱破碎岩质边坡的塌方主要是由于坡顶岩体的张拉和坡脚岩体的压剪共同作用的结果，且往往呈渐进性破坏机制；当采取锚杆加固时，一方面，锚杆加固可有效提高边坡岩体的承载能力和抵抗变形能力，锚杆的作用主要体现在抗剪止裂和抗拉伸两个方面，另一方面，不同的锚杆直径、锚杆长度和锚固间距对边坡岩体的加固效果和最终破坏模式有较大影响。

Experimental study on progressive failure properties of weak and fractured rock slopes with different anchoring modes

Cutting slopes in weak and fractured rock mass will inevitably induce excessive stress or deformation of the surrounding rock,which may result in slope collapse accidents.Therefore,a large number of anchor bolts are required to reinforce the rock mass.In order to further understand the failure mechanism and the anchoring effect of this kind of slope,the weak and fractured rock mass of grade Ⅳ,according to China’s classification,is taken as the reference prototype.It is equivalent to be isotropic continual stratum for facilitating research firstly,and then its geologic model ground is manufactured according to the similarity theory.Subsequently,a series of model tests are carried out to study failure characteristics of the rock slope with or without bolt reinforcement.The test results show that,if no reinforcement measures are taken,the collapse of slope is the combined results of tension failure at the top and compression-shearing failure at the bottom of the slope,and it often presents the characteristics of progressive failure.If bolts are adopted for reinforcement,on the one hand,it can effectively improve the bearing capacity and deformation resistance of rock mass,and the anchoring effect of the bolts is mainly reflected by the aspects of shear resistance,crack resistance and anti-extension;on the other hand,different bolt diameters,lengths and spacings have a great impact on the reinforcement effect and the final failure mode of the rock slope.