含水粘土断层泥的现场大尺度剪切实验

LARGE SCALE IN-SITU SHEAR EXPERIMENTS ON WATER-BEARING CLAY GOUGE

为了研究水分对断层泥抗剪特性的影响,在湖北省当阳县砂岩岩体中的天然断层带上进行了现场大尺度的剪切实验。实验用直剪法进行。试体的尺度为30×50×60cm^3。以含水粘土断层泥的天然断层面为剪切面。剪切面的面积为3000cm^2。先对试体在一个确定的正应力下进行剪断实验,然后继续对它在不同的正应力下进行摩擦实验。实验表明,剪断实验表现为塑性破坏及随后的位移强化现象。摩擦实验的摩擦强度略高于剪切破坏强度。剪切破坏强度方程为:τ=0.03+0.30σ。其中σ为正应力,τ为剪应力。单位均为MPa。

In order to study the cficct of water upon the gouge shearing resistance property, large scale in-situ shear experiments were made in the sandstone rockmass along the natural fault zone, Dangyang County, Hubei Province. The direct shear method was used in those experiments, with the specimen as large as 30×50×60 cm3. The natural fault plane that contains (he water-bearing clay gouge was taken as the shear surface, which has an area of 3000 cm2. The shear experiment was firstly made under a given normal stress and then the friction experiments were continuously made under different normal stresses. Those experiments have shown that a plastic tailure and the subsequent displacement increment took place during the experiments. In the friction experiment, the irictional strength was a little bit higher than the shear failure strength. The equation concerning the shear failure strength is: τ=0.03+0.30 σ, in which σ is the normal stress and τ is the shear stress, all in a MPa unit.