Abstract: To investigate the deformation mechanism and mechanical features of structured soils,triaxial compression tests on weakly bonded structured soils are conducted with the stress paths of axially loading—unloading—reloading.The samples are artificially prepared weakly bonded structured soils,which are tested under consolidation drained (CD) and consolidation undrained (CU) conditions with the confining pressures of 25 and 100 kPa,respectively.It is founded that,with increasing loading,the structured soils will be gradually de-structured and thus tend to behave as the reconstituted soils.Under CD conditions,during the whole axially loading-unloading-reloading processes,the structured samples contract as a whole;however,when the axial strain is smaller,the bonding between the particles remains relative intact and therefore unloading the samples will locally dilate or contract very slightly,which differ from the reconstituted clays.Under CU conditions,the positive pore pressures will occur,and unloading the pore pressures will reduce with the smaller axial strain and increase with the bigger one,having bigger increased values when the confining pressure is bigger.