Deformation And Strength Behavior Of Remoulded Loess In Taiyuan

Loess Plateau is one of the largest loess plateau in China,with the most widely distributed loess areas,the most complicated loess structure distribution,the most serious soil erosion areas,and the most fragile eco-environment areas.The loess plateau is the major coal and origin of industrial chemicals.The Develop-the-west Strategy has been implemented for more than ten years and many social infrastructures are under construction in Shaanxi,Shanxi,Gansu and Ningxia Province.The engineering properties and potential of loess are also an active topic in soil mechanics.In this study,the Shanxi province loess-the typical areas of loess plateau,mechanical characteristics remoulded loess was studied,including long-term compression characteristic,creep behaviors and rebounding behaviors.A series of undrained triaxial tests were performed,consisting of conventional triaxial compression tests(CTC),equal s triaxial tests(Triaxial compression tests-TC)and reduced triaxial compression tests(RTC).The effect of consolidation pressure and stress path on strength,deformation,pore water pressure was studied.In the chapter of 1-D compression tests,the stress-strain curves of saturated specimens are different and the inflecting points were located for 5 %and 20 % specimens.Instantaneous compression takes up a great proportion of total compression.Creep properties were considered as consisting of 3 parts and linear attenuation characteristics was observed.Rebounding coefficient of elasticity strain is semi-logarithmic linear relationship with the over consolidation ratio(OCR).Compression index of specimens decreases rapidly at a low saturation and slowly decreases with the increasing of saturation.Creep coefficient steady increase after a slight fluctuation,but most of its value less than 0.001.In stress path tests,triaxial results indicate the stress-strain characters are followed by strain hardening behavior under different stress-path tests.The deviatoric stress of conventional triaxial compression(CTC)tests is significantly greater than that of triaxial compression(TC)tests,especially the reduced triaxial compression(RTC)results are minimal.The internal friction angles follow by decreasing,with triaxial compression(TC)tests,triaxial compression(TC)tests and reduced triaxial compression(RTC)tests.The cohesions from conventional triaxial compression(CTC)are significantly larger than those from reduced triaxial compression(RTC)and triaxial compression(TC)tests.The effective s'-t curve shows a consistent trend.At the ultimate state,close to the failure envelope,characterized by V-shaped curve.The pore-water pressure increases with the increase of axial strain.Anda peak was in the initial phase of the tests.It generally regarded as structural failure point.After the peak,the pore water pressure shows consistent decreasing trend for each test.