Gemara

R. Aba: If someone dug a pit on Shabbos and needed only the dirt, he is exempt.

Suggestion: This is like R. Shimon, who exempts for Melachah she'Einah Tzerichah l'Gufah!

Rejection: It is even like R. Yehudah (who is Mechayev). R. Yehudah is Mechayev only for something constructive. This is destructive!

Beitzah 23b - Mishnah: A child's wagon may be dragged only over Kelim;

R. Yehudah says, a wagon is the only Keli which may be dragged (on dirt), for it (has wheels and merely) compresses the dirt underneath.

Ran (DH Masnisin): After it is dragged a furrow is seen. However, this was not done by digging (removing dirt), rather, by compressing it.

Rav Nachman: This is R. Yehudah's opinion, but the Halachah follows R. Shimon who permits to drag a bed, chair or bench as long as he does not intend to make a furrow.

Shabbos 29b: Avin of Tzipori dragged a bench on a stone floor of an Aliyah (upper story) in front of R. Yitzchak ben Elazar.

R. Yitzchak: This is forbidden. We decree about a stone floor of an Aliyah lest one do so in a regular Aliyah (with a dirt floor; dragging could make a furrow).

The overseer of the Beis ha'Keneses in Botzrah dragged a bench on a stone floor in front of R. Yirmeyah Sava.

R. Yirmeyah: You do so for you hold like R. Shimon? R. Shimon permits only big benches, which one cannot carry. He forbids dragging a small bench, for one can carry it!

R. Yirmeyah argues with Ula:

(Ula): R. Shimon and R. Yehudah argue about small benches (and R. Shimon permits), but all permit a big bench!

Question (against R. Yirmeyah and Ula - Rav Yosef - Beraisa - R. Shimon): One may drag a bed, chair or bench, as long as he does not intend to make a furrow;

(In the Seifa, R. Yehudah forbids everything except for a wagon, for it does not make a furrow.) This shows that they argue about big and small Kelim!

Answer #1 (for Ula): The bed discussed is small, just like a chair (which is taught with it).

Answer #2 (for R. Yirmeyah): The chair discussed is big, just like a bed (which is taught with it).

Rishonim

The Rif and Rosh (Beitzah 12b and 2:25) cite the Gemara which says that the Halachah follows R. Shimon regarding dragging as long as he does not intend to make a furrow.

Rambam (Hilchos Shabbos 1:5): If something is permitted on Shabbos, but it is possible but not certain that a Melachah will be done through it, it is permitted if one does not intend for the Melachah. One may drag a bed, chair or bench (on a dirt floor), as long as he does not intend to make a furrow. If it made a furrow he need not be concerned, for he did not intend for this.

Magid Mishnah: The conclusion in Shabbos (29b) is that benches of all sizes are permitted. This is why the Rambam did not specify the size of the bench.

Rambam (17): Anyone who did a destructive act is exempt. If someone dug a pit and needed only the dirt, this is destructive, so he is exempt. Even though he did a Melachah, since he intended to ruin he is exempt.

Kesef Mishneh: The Ramach says that the Rambam should have specified that one is exempt only in the house, but not in the field, for the Rambam is Mechayev for Melachah she'Einah Tzerichah l'Gufah like R. Yehudah. There was no need for the Rambam to specify. It is clear from his words, like the Magid Mishnah says (if the hole was in a place where it is not destructive, even if he does not need it he is liable).

Poskim

Shulchan Aruch (OC 337:1): Davar she'Eino Miskaven is permitted (on Shabbos) as long as it is not a Pesik Reishei. Therefore one may drag a big or small bed, chair or bench. One may sprinkle water on the floor, since he does not intend to even out holes, only to prevent dust from rising in the wind.

Beis Yosef (DH u'Mah she'Chasav Hilkach): The Rambam did not specify the size of the bed, chair or bench; presumably, he permits any size (like the Rif and Rosh), as long as it is not a Pesik Reishei (that it will make a furrow). The Re'em forbids small Kelim even on a stone floor, for one can carry them; he must have had a different text in the Gemara. However, if a Keli is so big that it is a Pesik Reishei, it is forbidden even on a stone floor.

Kaf ha'Chayim (4): A wagon of any size is permitted, for it compresses dirt. It does not make a furrow.

Beis Yosef (ibid.): R. Shimon permits Davar she'Eino Miskaven regarding anything which is not forbidden mid'Oraisa with intent (Shabbos 46b). Making a furrow is mid'Oraisa only with a shovel or a similar tool.

Mishneh l'Melech (Shabbos 1:5): From the conclusion in Shabbos (46b) we learn that R. Shimon permits even regarding Isurim mid'Oraisa. In the Hava Amina, R. Yehudah forbids even regarding mid'Rabanan laws; this appears to be true also in the conclusion. Rashi (Yoma 34b DH b'Chol) holds that even R. Yehudah permits regarding Isurim mid'Rabanan; Tosfos (Yoma 34b DH Hani) refutes Rashi, but perhaps Tosfos (Kesuvos 5b DH Im) agrees with Rashi.

Note: It appears that the Beis Yosef means like he wrote in Sof Siman 265, 'the Halachah follows R. Shimon, and all the more so here in a mid'Rabanan matter'. We should not be Medayek that Davar she'Eino Miskaven is forbidden regarding mid'Oraisa Isurim. Regarding Davar she'Eino Miskaven the Gemara often says 'the Halachah follows R. Shimon', it never says that the Halachah follows R. Yehudah regarding something mid'Oraisa. The Shulchan Aruch permits Davar she'Eino Miskaven regarding Isurim which are mid'Oraisa with intent, e.g. Kil'ayim (YD 301:6) and detaching grass (OC 312:3). The Shulchan Aruch forbids sweeping and other actions prone to even out holes; the Beis Yosef never says that we are concerned for R. Yehudah regarding mid'Oraisa Isurim. The Kaf ha'Chayim (1) cites the Beis Yosef, then cites Poskim who permit even regarding Isurim which are mid'Oraisa with intent, and says that this is unlike the Levush.