某水电坝基柱状节理玄武岩固结灌浆试验研究

Consolidating Grout Testing in a Basalt Bedrock with Columnar Joints for a Dam Foundation

柱状节理岩体作为一种特殊的岩体,地质结构特点与常见岩体有很大不同。柱状节理面起伏、不规则,柱体断面不规则且切割不完全,柱体内隐裂隙发育、变形模量较低,层间层内错动带发育,变形及抗剪强度均较低,部分岩性段还存在劈理密集带。作为拱坝的坝基岩体,要求有足够的承载力和稳定性,由于柱状节理岩体特殊的岩体结构、结构面发育特征等,应充分了解柱状节理玄武岩、弱风化下段弱卸荷岩体、层间层内错动带、断层影响带等经灌浆处理后其整体性、刚度和强度的提高幅度及相应的岩体力学参数,为加大基础抗变形能力、提高结构面抗剪抗渗能力,有必要对坝基开展固结灌浆试验,研究论证灌后岩体作为拱坝基础的可行性和可靠性,为坝区岩体固结灌浆的合理设计和确定施工参数提供参考。

as a special rock mass,rock mass with columnar joints has a different geological structure with the conventional rock masses.The columnar joints are generally having irregular and variable joint plane and the cross section of the columnar joints are also irregular and have incomplete incision.Joints and fissures are well developed inside the columnar structures and these defects contribute to the relatively lower modulus and low shear strength.The concentrated split zones can also be observed in same rock mass.As the foundation of a concrete arch dam,the rock mass is required to have sufficient bearing capacity and stability.However,due to the unique tectonic structure of the columnar jointed rock mass with well-developed structural planes,it is necessary to evaluate the performance of the basalt bedrock with the columnar joints under the loading conditions as well as the impact of the consolidating grout at the faulted and broken zones on the integrity,strength and stiffness parameters.The consolidating grout reduced the deformation resistance,increased the shear strength and remediated the seepage at the structured plane of the rock mass.