On the basis of in situ direct shear tests the effect of roughness, concrete strength and normal stress on the shear strength of the cemented interface between concrete and bedrock has been systematically studied. As a result of this study, an efficient method for assessing the shear strength of the cemented interface is presented.

Taking the north anchor foundation pit of the suspension bridge at the south part of Runyang Bridge as an example, the factors that influence the shear strength of cemented interface between concrete and bedrock are analyzed.

Through the zoning the bedrock surface is analyzed and the formula for the determination of the shear strength of the whole anchor foundation is proposed. The rationality of the said method to determine the shear strength of the whole cemented interface between concrete foundation and bedrock is discussed by considering multi-factors and tests.

An apparent nonlinear relation of normal stress versus shear stress is obtained after determining the relationship between non-dimensional ratio τ/Rc--σn/Rc. By using the equation of the curve fitting, the shear strength of the cemented interface between any concrete strength required in construction and bedrock can be obtained.

The study shows that the roughness is a major factor which influences shear strength. The shear strength for design can be basically estimated according to the basic friction angle and the peak dilation angle of the interface, and the shear strength of the cemented interface without normal stress.

On the basis of in situ direct shear tests the effect of roughness, concrete strength and normal stress on the shear strength of the cemented interface between concrete and bedrock has been systematically studied. As a result of this study, an efficient method for assessing the shear strength of the cemented interface is presented.Due to the varieties of concrete strengths the test results of τ-σn seem to be scattered.An apparent nonlinear relation of normal stress versus shear stress is obtained...

On the basis of in situ direct shear tests the effect of roughness, concrete strength and normal stress on the shear strength of the cemented interface between concrete and bedrock has been systematically studied. As a result of this study, an efficient method for assessing the shear strength of the cemented interface is presented.Due to the varieties of concrete strengths the test results of τ-σn seem to be scattered.An apparent nonlinear relation of normal stress versus shear stress is obtained after determining the relationship between non-dimensional ratio τ/Rc--σn/Rc. By using the equation of the curve fitting, the shear strength of the cemented interface between any concrete strength required in construction and bedrock can be obtained.The study shows that the roughness is a major factor which influences shear strength. The shear strength for design can be basically estimated according to the basic friction angle and the peak dilation angle of the interface, and the shear strength of the cemented interface without normal stress.Therefore, in order to determine the shear strength of the cemented interface between concrete and bedrock, it is extremely important to obtain the basic friction angle of concrete against the plane-surface of the bedrock; make measurement of the peak dilation angle and the shear strength without normal stress; and determine the concrete strength during the direct shear tests under appropriate roughness.

Corresponding to various shear strength with even stress distribution,the real shear strength of cemented interface between concrete and bedrock is studied in this paper by elasto plastic FEM.The effect of Young's modulus of concrete and rock upon the real shear strength is analyzed,and the influence of sample shape on the test result about shear strength is studied too.Some propositions that can be taken as references for engineering practice and in situ shear test are put forward.

In the fracturing process for making the horizontal fractures, the interlayer channeling often takes place. In order to investigate the causes of interkyer channeling, the finite element numerical simulations were carried out by means of the software ANSYS. The results demonstrate that the interkyer channeling is resulted from the shear destruction of the second cemented interfaces nearby. The shear destruction is induced by the imbalance of pressures acted on the upper and lower surfaces of interlayer....

In the fracturing process for making the horizontal fractures, the interlayer channeling often takes place. In order to investigate the causes of interkyer channeling, the finite element numerical simulations were carried out by means of the software ANSYS. The results demonstrate that the interkyer channeling is resulted from the shear destruction of the second cemented interfaces nearby. The shear destruction is induced by the imbalance of pressures acted on the upper and lower surfaces of interlayer. The lowest limits of interlayer thickness for the balance fracturing technology and the ordinary fracturing technology were determined on a series of calculations. When the thickness of interlayers is over the limits for these two technology,the interlayer channeling would probably take place in the practice. This result may provide a quantitative reference for putting the balance fracturing technique into practice.