def calc_shear_vel_andrus_and_stokoe_2000_spt_values(n_1_60):
    """
    Eq 98 in Pm4Sand v3.1 manual

    :param n_1_60:
    :return: float or array_like
    """
    return 85.8 * (n_1_60 + 2.5) ** 0.25