The Original Entrance.
http://www.ancient-wisdom.co.uk/Ghizaarchitecture.htm#2.20

» The true entrance to the great pyramid was bypassed by Al Mamun in 820 AD. The original entrance into the pyramid was through the now missing door at the top of the Descending corridor, a feature common to other early dynastly pyramids. The door was described by Strabo around 24 BC, who said that it swivelled open. It is noticeable in Strabo’s text that he mentions a hidden door on the south face of the pyramid, while the door is actually on the north face. The stones that surround the entrance are some of the largest used in the pyramid. What we see today of course is not the entrance as it was intended to be seen because the casing stones and masonry surrounding it have been removed. Rather, we are able to see the remains of what appears have been an exercise in extreme engineering. How these huge stones and the immense corbel’s relate to the final doorway placed/hidden into an otherwise flat surface is a mystery. The architecture of the entrance raises some interesting points such as the fact that apart from the unnecessary extra work involved in building with such huge stones or the apparent pointlessness of having an opening door for a tomb never to be disturbed, there is also the matter of the symbol carved over the doorway (ph. left). Apart from being a curious choice of location, there is little if no agreement on what its meaning might be. The vague similarity to the Egyptian hieroglyph for the word ‘Horizon’ has led to the suggestion that this symbol might be a representation of that word. «According to Walter Marshall Adams, the triangle was meant to symbolize the ‘door of the horizon’, the hieroglyphic sign for the horizon…having been carved inside the triangle, which from a distance, assumes the form of a pupil. Thus, Adams believes, the hieroglyphic sign must be the pyramids divine name».
(More about the Original Doorway)  The Entrance: Strabo mentioned a hidden ‘South’ door, which presumably remained until Al-Mamun’s time, as he apparently failed to find it. We know that doors were put into other pyramids. For example: (Extract from Petrie, 1883) ‘The traces of a stone flap door, or turning block, in the mouth of the South Pyramid of Dahshur, have been already described (section 109), as well as the signs of a wooden door behind that. Such a formation of the passage mouth is unmistakable in its purpose; but after drawing conclusions from that doorway, it was a most satisfactory proof of the generality of such doors, to observe the following passage from Strabo on the Great Pyramid. «The Greater (Pyramid), a little way up one side, has a stone that may be taken out , (exairesimon, exemptilem) which being raised up (arqentoV, sublato), there is a sloping passage to the foundations.» This sentence is most singularly descriptive of opening a flap door; first, the stone is taken out, or lifted outwards from the face; and then, being thus raised up, the passage is opened. The two different words exactly express the change in the apparent motion, first outwards and then upwards; and they show remarkable accuracy and precision in their use. Besides this description, there is another statement that the Pyramids of Gizeh had doors, in an Arabic MS., quoted by Vyse; this was written in 850 A.D., and, therefore, only twenty or thirty years after Mamun had forced his way into the Great Pyramid, and thus re-discovered the real entrance’. An original translation of Strabo’s Geographica dating to 1857, says: «…a stone, which may be taken out; when that is removed»—not «raised up». The translation of the original Greek is clearly important. Conclusion — Strabo talks specifically of a ‘hidden’ entrance on the South (North) face with an opening door. The fact that the entrance and descending passage was not described for so long after this suggests that it was ‘closed’ until the entry by Al-Mamun. This clearly suggests that there was a door which could be either open or closed and ‘Hidden’. Petrie’s study of the Bent (Vega) Pyramid (The only pyramid with remaining doorways around the intact entrance), found that on either side of the entrance, there were holes cut opposite each other, about 9cm in diameter by 14 cm deep. These holes were just inside the entrance and only 15cm from the top of the passage. Petrie interpreted these as being hinge sockets to swing a stone door from. Behind these sockets, the passageway contained more door sockets. These were smaller vertical sockets for a very lightweight door. The following two prints are from Petrie, 1882. The mechanical proofs of the existence of a door to the Great Pyramid are of some weight, though only circumstantial, and not direct evidence like that of the above authors. No one can doubt that the entrance must have been closed, and closed so as not to attract attention at the time when the Arabs made their forced passage, about a hundred feet long, through the solid masonry. Moreover, it is certain that the entrance was not covered then by sand or rubbish: (i) because the Arabic hole is some way below it, and the ground-level at the time of the forcing is seen plainly in the rubbish heap; (ii) because the rubbish heap, which is even now much below the original doorway, is composed of broken casing, and the casing was not yet broken up at the time of forcing the passage. Therefore the doorway must have been so finely closed that the various accidental chippings and weathering on all the general surface of the casing completely masked any wear or cracks that there might be around the entrance; and so invisible was the door then, that, standing on the heap from which they forced their hole, the Arabs could not see anything to excite their suspicion on the surface only 35 feet above them; they, therefore, plunged into the task of tearing out the stone piecemeal, in hopes of meeting with something in the inside. Yet we know from Strabo that the Romans had free access to the passage, though he says that it was kept a secret in his time. No extractable plug or block, weighing necessarily some tons, would have been replaced by every visitor until the Arab times, especially without there being any shelf or place to rest it on while it was removed.* * Exactly the same reasoning applies to the Second Pyramid. Diodorus Siculus mentions the foot-holes up to its entrance, and Herodotus correctly describes the form of its passages and yet the Arabs forced a large passage in it, in entire ignorance of the real entrance, which must, therefore, have had a door like the Great Pyramid. (This all assumes that the ‘Arab’s’ had no knowledge of the door, whereas it is also possible that they had complete knowledge of it). The restoration of a door would agree to these various historical requirements, and be in harmony with the arrangement at Dahshur such a block would only need a pull of 2.5 cwt. on first taking it outwards, and 4 cwt. to lift it upwards to its final position; it would leave no external opening; it would also allow just half of the passage to be quite clear; and from the passage being halved in its height by two courses at the beginning, such an opening is the most likely. Though the general form is thus indicated, the details are of course conjectural. Some photos of the Gabled entrance:- The whole entrance is considerably set back from the face and is not easily visible from below. These features would have all been hidden by the original casing stones. Note: It was suggested by Lepre that the perforated stone in the bottom-left photo is one of the missing ‘Portcullis stones’ from the ‘Kings’ ante-chamber. According to Walter Marshall Adams, the triangular area above the doorway was meant to symbolize the ‘door of the horizon’, the hieroglyphic sign for the horizon… having been carved inside the triangle, which from a distance, assumes the form of a pupil. Thus, Adams believes, the hieroglyphic sign must be the pyramids divine name». This symbol should be considered of the highest significance…It serves no structural function and is therefore representative of something. It is one of the most unique and unexplained architectural features of the Great Pyramid.

Les deux entrées de la Grande Pyramide, selon l’interprétation de Michel Michel (”Khoufou”)
http://pyramidales.blogspot.com/search/label/Goidin%20%28Jean-Patrice%29

Les forums “sérieux” traitant de pyramidologie ne sont pas légion.pPs1
Ddchampo.com en fait indéniablement partie.pPs2
Or c’est précisément dans le contenu de cet espace d’échanges entre internautes que Michel Michel, alias Khoufou, a ouvert un “topic” sous le titre “L’entrée de la pyramide de Chéops”.
Ce sujet a donné lieu à de nombreuses et parfois volumineuses contributions qu’il m’est impossible (et déontologiquement interdit) de reproduire ici.
Khoufou le résume et illustre ainsi, pour les lecteurs de Pyramidales.
En 1986, Gilles Dormion et Jean-Patrice Goidin posent sur la Grande Pyramide un regard d’architectes modernes. L’entrée de la pyramide les interpelle tout particulièrement.
Le couloir descendant (A), large de seulement 1,04 m, est couvert par trois plaques linteaux (B) de 20 tonnes chacune, un épais linteau crénelé (C), et une double couverture à chevrons (D).
Cette débauche de protections leur semble démesurée car, pour couvrir un couloir de même largeur, les architectes des pyramides de Khéphren et de Mykerinos ont eu recours à un simple linteau (E).
pPs3Ils observent, par ailleurs, que les lits d’attente (en vert) sur lesquels s’appuient les chevrons du niveau inférieurpPs4 se prolongent sur une distance qui leur permettrait d’accueillir sept paires de chevrons, et qu’un autre lit d’attente, encore visible à l’Est, permet d’accueillir quatre paires de chevrons au niveau inférieur. En outre, deux abouts de chevrons brisés reposent encore sur ce lit d’attente, ce qui démontre qu’à l’origine, l’entrée étaient couverte par une double couverture à chevrons sur une distance de 4,60 m et sur une largeur de 3,15 m, comme ceci :
(Plaques stockées à plat);
(Plaques masquant l’entrée du second couloir).

“Dans toutes les constructions de l’histoire, précisent les deux auteurs, une voûte a toujours servi à ménager, par le vide qu’elle dégage, un espace libre ne recevant aucune pression.
Il n’était pas nécessaire de protéger le dessous de cette voûte par une succession de plaques linteaux.”
Ils suggèrent que cette “antichambre” était destinée au stockage des trois plaques-linteaux qui servaient à masquer l’entrée d’un second couloir, au-dessus du couloir descendant.pPs6pPs5
Si je partage totalement l’idée d’une antichambre permettant le stockage du mécanisme de fermeture d’un second couloir, en revanche, je conteste cette reconstitution, car elle est impraticable.
À mon avis, le projet initial devait ressembler à ça : Cette coupe 3D montre la moitié Ouest de l’entrée.
On y voit deux blocs-bouchons (A et A’) stockés temporairement dans les dégagements latéraux de l’antichambre (2 autres à l’Est).
Ce positionnement permet de ménager un passage large de 1,04 m pour accéder au second couloir. Ces bouchons sont larges de 1,04 m, longs et hauts d’environ 2 m et peuvent être aisément déplacés latéralement comme le suggèrent les flèches.
Suite à l’effondrement de la voûte et à la destruction de ce qui se trouvait dessous, trois plaques linteaux ont été récupérées parmi celles qui se trouvaient initialement en B, et placées là où on les voit aujourd’hui.
Si une seconde entrée existe, où mène-t-elle ?pPs7
Suite à l’effondrement de l’antichambre, cette seconde entrée aurait été inutilisable, rendant le réseau supérieur inaccessible.
Le couloir ascendant (en vert) aurait été raccordé (pointillés) au couloir descendant (en jaune), en creusant directement à travers la maçonnerie environnante.
Enfin, le couloir bleu aurait été bouché à chacune de ses extrémités.