Experimental study on bearing capacity of moderately weathered mudstone in Chengdu area

The moderately weathered mudstones in Chengdu area are widely developed. The code DB51T5026 recommends that the characteristic value of bearing capacity is 500~1000 kPa, which is determined by the reduction method for uniaxial compressive strength of rock. However, the engineering practice proves that the proposed value is low, but there have been few breakthroughs in its researches. We discuss the value of reduction factor and its correlation with f_a for the moderately weathered mudstone in Chengdu area, based on the comparative analysis of 24 sites of in-situ load tests and uniaxial compressive strength tests. Furthermore, based on a super high-rise building project under construction in the High-tech Zone of Chengdu, the bearing capacity of the mudstone foundation f_a is determined by using the bearing plate tests and the pressuremeter tests. The results show that the values of f_a determined by the tests are 1500~2500 kPa. The reduction coefficient of uniaxial compressive strength from high to low can be 0.37~0.7. For the mudstones with the same character, the diameter of the bearing plate has no significant effect on f_a; and the values of f_a determined by the bearing plate tests and the pressuremeter tests are very similar. The research results put forward the value of bearing capacity of moderately weathered Jurassic mudstone in Chengdu area, and a fast and economic estimation method to determine the characteristic value of bearing capacity of this kind of mudstone foundation. At the same time, the research results have a certain engineering value for giving full play to the bearing capacity of red bed soft rock.