Granted but, Do you mean 3 times bigger mass? Do you mean 3 times bigger radius? Do you mean 3 times bigger volume?
Those are three different things.
Changing any of these will affect the Earth's gravity. The acceleration due to gravity is given by:
g=GM/R2=9.8m/s2
G is the gravitational constant, 6.67x10−11m3kg−1s−2
M is the mass of the Earth, 5.972x1024kg
R is the radius of the Earth, 6,371km or 3,959mi
If mass increases by 3 times, but radius stays the same, then the Earth's gravitational pull would be 3 times bigger.
If the radius was 3 times bigger with the same mass, than the gravitational pull would be 1/9th instead.
If both the mass and radius were 3 times bigger, the gravity would be would be 1/3rd.
If density is what you are holding constant then if the volume is 3 times bigger, then the mass would also be 3 times bigger. The radius in this case would be 3√3≃1.44 times what it was before and the gravity would be 9√3≃2.08 times what it was before.
If density is what you are holding constant and the radius is 3 times bigger, then the mass would be 27 times bigger, and the gravity would be 3 times bigger.
In any circumstance you are increasing the radius, you are increasing that much squared in terms of the Earth's surface area too, as well as the inertia involved with its rotation. Any changes to the Earth's surface gravity would have huge ramifications for life on Earth, its atmosphere, and its oceans. Any change in the mass would effect the orbit of the moon, and tides.
Basically it all depends on what specific aspect of the Earth we're talking about and what changes with it.
I wish my car never ran out of fuel