This proposal is a part of an investigation of U(1) spin liquid states, quadrupole ordering, and their quantum phase transition in a frustrated pyrochlore magnet Tb_{2+x}Ti_{2-x}O_{7+y}. In spin ices, finite zero-point entropy and magnetic monopole excitations have attracted much attention. Spin ices are well represented by a classical Ising Hamiltonian. When spin-flip terms are added to this spin-ice Hamiltonian, very interesting quantum many-body effects emerge from the macroscopically degenerate ground state. This is referred to as "quantum spin ice", in which the phase angles of the spinors become correlated in such a way that a U(1) gauge field emerges. In the U(1) spin liquid state, the U(1) field is fluctuating down to T = 0, where gapped spinon and gapless photon excitations are predicted. By changing interaction parameters, the system undergoes a phase transition to a LRO states. A simple pseudo-spin ordering is the putative quadrupole ordering of Tb_{2+x}Ti_{2-x}O_{7+y}. The purpose of this proposal is to get convincing evidence for this quadrupole ordering using inelastic neutron scattering.