Abstract: Aiming at the shortcoming of the existing consolidation theories of composite ground without considering nonuniform distribution of initial excess pore water pressure in practical engineering, the consolidation theory of composite ground with granular columns is studied in-depth by analytical method; and a general analytical solution is given to the consolidation problem for the composite ground with granular columns under nonuniform distribution of initial excess pore water pressure. The three special cases for nonuniform distribution of initial excess pore water pressure are discussed; and the expressions of average excess pore pressure and average degree of consolidation are derived under the rectangular (uniform), triangle and inverted triangle distribution of initial excess pore pressures. The results show that the distribution of initial excess pore water pressures has obvious influence on the consolidation of the composite ground with single drainage boundary. Under the uniform and triangle distribution of initial excess pore pressure, the excess pore water pressure dissipates gradually with the increase of Tv, and the one is always maximal at the bottom of foundation during consolidation; under the inverted triangle and trapezoidal ( pB /pT =0.5) distribution of the initial pore water pressure, the Tv value is bigger, the excess pore water pressure isochrones are gentler, and the position of maximal excess pore pressure shifts from the top of foundation to the bottom; the change of excess pore water pressure reflects the characteristic “from small to big, and then smaller” in the consolidation process.

Key words: composite ground with granular columns, consolidation, nonuniform distribution of initial excess pore water pressure, excess pore water pressure isochrones, analytical solution