In nature, soils could be compacted due to its own weights, external loads and internal forces as a result of wetting and drying processes. Intrinsic soil properties such as texture and dynamic properties such as water content and external loads are recognized as being important factors influencing soil compactibillity. Soil compaction in sugarcane fields usually occurs due to mechanized harvesting operations by using heavy machinery in wet soils. Adding plant residues to the soil can improve soil structure. Estimating soil stress at compaction threshold (pre-compaction stress, ? pc ) and the soil sensitivity to excess compaction (deformability coefficient, C D or compression index, C C ) when the applied stresses due to the field traffic exceed the ? pc , can be useful to prevent soil compaction. The objective of this research was to investigate the effect of adding sugarcane residues (i.e. bagasse and filter cake) with different rates (0, 1 and 2%) on ? pc and shear strength of a silty clay loam soil and finding relation between pre-compaction stress and soil shear strength. Disturbed soil samples were collected from topsoil (0?20 cm layer) of the Agricultural Research Farm, Isfahan University of Technology. Sugarcane residues (bagasse and filter cake) were obtained from the sugarcane fields in Ahvaz, Khuzestan province. The compressive properties (? pc , C D and C C ) of the soil with or without wetting and drying cycles at two water contents of 0.9PL and 1.1PL (PL= plastic limit) were determined using plate sinkage test (PST) and confined compression test (CCT) under two cycles of loading (200 and 400 kPa). Soil shear strength parameters (cohesion, c and internal friction angle, ?) were measured using a direct shear box test. Stress-sinkage and stress-strain curves were drawn for both PST and CCT, respectively. For each curve three different methods were considered to determine the ? pc . These methods were: (1) Casagrande method, (2) maximum curvature, and (3) intersection of virgin compression line (VCL) and x axis. The effects of wetting and drying cycles, soil water content, residues type and percent on soil compressive properties and shear strength were studied using a factorial experiment in a randomized complete block design with three replications. Results showed that in PST, the maximum and minimum values of ? pc were obtained with Casagrande and maximum curvature methods, respectively. In CCT, the Casagrande method underestimated and overestimated the ? pc values when compared with the intersection of VCL and x axis and maximum curvature methods, respectively. Upon 5 cycles of wetting and drying, the ? pc decreased about 30.3 and 6.3% in PST and CCT, respectively, when compared with no wetting and drying. In the residue-added treatments (compared to the control) the ? pc decreased by 83 and 14.1% when the water content increased from 0.9PL to 1.1PL, respectively. With 5 cycles of wetting and drying compared to no wetting and drying, the C D in PST decreased by about 30%. Adding filter cake to the soil increased, the C D in PST by 14.3% and decreased the C C in CCT by 3% when compared with bagasse. When the water content increased from 0.9PL to 1.1PL, the C D and C C increased and decreased by 19 and 32%, respectively. The soil c and ? decreased upon wetting and drying and when water content increased from 0.9PL to 1.1PL. Compared to bagasse, filter cake application to the soil increased and decreased, c and ? by about 15.2 and 10%, respectively. The c increased and the ? decreased by adding residues to the soil. Residue application increased the soil sinkage after both loading cycles. The water content increment from 0.9PL to 1.1PL increased the soil sinkage after first (200 kPa) and second (400 kPa) loading cycles by 35.0 and 23.4%, respectively. Therefore, in order to manage the compaction of the soils which have been retrofitted by adding residues, it is recommended that in order to prevent soil structure deterioration, in addition to the load reduction during trafficing, the field operation should be carried out at lower water content. Keywords: Pre-compaction stress, Deformability coefficient, Compression index, Shear strength, Wetting and drying, Cohesion, Internal angle of friction.