Scientists estimate that its stone blocks average over two tons apiece, with the largest weighing as much as fifteen tons each. Also located at Giza is the famous Sphinx, a massive statue of a lion with a human head, carved during the time of Khafre. Pyramids did not stand alone but were part of a group of buildings which included temples, chapels, other tombs, and massive walls.
Remnants of funerary boats have also been excavated; the best preserved is at Giza. On the walls of Fifth and Sixth Dynasty pyramids are inscriptions known as the Pyramid Texts, an important source of information about Egyptian religion.
The scarcity of ancient records, however, makes it difficult to be sure of the uses of all the buildings in the pyramid complex or the exact burial procedures. It is thought that the king's body was brought by boat up the Nile to the pyramid site and probably mummified in the Valley Temple before being placed in the pyramid for burial. There has been speculation about pyramid construction. Egyptians had copper tools such as chisels, drills, and saws that may have been used to cut the relatively soft stone.
The hard granite, used for burial chamber walls and some of the exterior casing, would have posed a more difficult problem. Workmen may have used an abrasive powder, such as sand, with the drills and saws. Knowledge of astronomy was necessary to orient the pyramids to the cardinal points, and water-filled trenches probably were used to level the perimeter.
A tomb painting of a colossal statue being moved shows how huge stone blocks were moved on sledges over ground first made slippery by liquid. The blocks were then brought up ramps to their positions in the pyramid.
Finally, the outer layer of casing stones was finished from the top down and the ramps dismantled as the work was completed.
The paper shows a thorough analysis of the current condition of the Great Pyramids at Giza. The work includes a discussion and analysis of the natural character and source of the pyramids building stones, geological context, damage survey, petrographic investigation, and physical and mechanical characterization of the stones and structural mortars, by means of laboratory and in situ testing.
The results are displayed, described and analyzed in the paper in the context of potential threats to the monuments. The experimental study indicates the dependence of mechanical geological properties on the physical properties and the mineral composition of the studied building materials. The physical and petrographic characteristic of the stones are related.
The modeling of properties indicates a reliable relationship between the various visible pores and uniaxial compression force parameters that can be applied to predict and characterize limestone elsewhere. The Pyramids of Giza are the largest and most famous pyramid structures in the world.
It was built to honor some pharaohs of the Fourth Dynasty of Egypt during a period known as the Old Kingdom.
Pyramids of Giza, fourth Dynasty about — BC pyramids were erected on a rocky plateau on the west bank of the Nile near Giza in northern Egypt. In ancient times, they were included in the Seven Wonders of the ancient World. The Pyramids of Giza, built to endure forever, did exactly this. Archaeological tombs are remnants of the Old Kingdom of Egypt and were built about years ago. Pharaohs thought in the resurrection, that there is a second life after death.
To prepare for the next world, they set up temples of gods and huge pyramid tombs for themselves—filled with all the things each ruler would need to guide and preserve in the next world [ 1 , 2 , 3 ].
Its largest pyramid is the largest in Giza and is about ft. Its stone masses estimated at approximately 2. The great pyramid builders used stones of different sizes and heights for the different layers. For the layers that are higher up, it was easier to transport smaller blocks 1. For calculations most Egyptologists use 2.
About , tons of mortar was used in the construction of the great pyramid. Many of the casing stones and inner chamber blocks of the Great Pyramid were fit together with extremely high precision. Based on measurements taken on the north eastern casing stones, the mean opening of the joints is only 0. There are three known chambers inside the Great Pyramid as follows: a The lowest chamber is cut into the bedrock upon which the pyramid was built and was unfinished.
The Great Pyramid of Khufu at Giza is the only pyramid in Egypt known to contain both ascending and descending passages. Originally, the Great Pyramid was provided with a stone cladding that formed a smooth outer surface; what is seen today is the underlying core structure.
The cladding can still be seen around the top part of the Pyramid [ 4 ]. As shown in Fig. The Sphinx may stand guard for the entire tomb of the Pharaoh, as shown in Fig. One-third of the pyramids of Giza are much smaller than the first two. The Menkaure pyramid is built at the far end of the Giza diagonal on the edge of the Mokattam formation, where it dips down to the south and disappears into the younger Maadi formation.
The complex includes a valley temple, a causeway, and a mortuary temple on the east side of the pyramid. The bottommost 15 m of the pyramid were cased with granite blocks from Aswan.
Further up, the casing was made of fine limestone. Each huge pyramid is only one part of a larger complex, including palace, temples, solar boat pits, and other features, see Fig. The Giza plateau was in ancient times, geologically connected to the Moqattam hill on the other side of the Nile crossing the site of what is now the capital Cairo.
The top level of the Giza plateau must have acquired a level hypothetically close to the Moqattam surface level, i. That axis almost coincides with the axis connecting the centers of gravity of the three pyramids. The lower stratum is identified as denser and more homogeneous. Conservation of historic buildings and archaeological sites is actually one of the most difficult challenges facing modern civilization. It involves a number of factors belonging to different areas cultural, human, social, technical, economic and administrative , intertwined in inseparable patterns.
The complexity of the topic is that it is difficult to imagine guidelines or recommendations that summarize what needs to be done and describe activities to continue, intervention techniques, design approaches.
From the point of view of the engineer, the specificity of this type of intervention is a requirement of respect for safety, along with ensuring safe use. Topography, geology, climate and human actions seem to have a significant impact on environmental processes, and therefore a significant impact on the conservation of the built environment.
The pyramid complex suffered from different types of structural damage and construction materials decay and disintegration. The sources of this degradation can generally be classified as: nature, time, and man-made. In recent years, the great pyramids and the Great Sphinx have been threatened by rising groundwater levels caused by water infiltration from the suburbs, irrigation canals and mass urbanization surrounding the Giza plateau [ 7 ].
The rising of groundwater levels represents a threat to the Egyptian Heritage of the Giza Pyramids Plateau GPP particularly since the area surrounding the plateau has been developed into the suburb of Greater Cairo. Today, Giza is a rapidly growing region of Cairo. Population growth in Egypt continues to soar, leading to new construction. New roads for large new developments are increasing obviously in the desert hills northwest and southwest of the Giza pyramids, As shown in space station views in Fig.
Roads and new constructions for large new developments are obvious in the desert hills northwest and southwest of the Giza pyramids. The new constructions in the desert hills northwest and southwest of the Giza pyramids rapidly increased.
The new constructions in the desert hills northwest and southwest of the Giza pyramids extended many times. The new constructions in the desert hills northwest and southwest of the Giza pyramids.
Understanding the passage ways of rain water on the plateau, groundwater and sewage from both the Nile flood plain and Abo Roash area play an important role in the conservation strategy for the unique artifacts of the Giza Plateau Two regional aquifers are located behind the Sphinx statue with a water level at a depth of 1. The second aquifer is a broken carbon aquifer that covers an area beneath the pyramid and sphinx plateau, where the depth of the groundwater ranges from 4 to 7 m.
The recharge of the aquifer underneath the Sphinx area occurred mainly through diversion of the water network and overall urbanization [ 7 ]. Due to the unique values of the three great pyramids in Giza, the present work is very important to analyze the nature and sustainability of the construction materials of the pyramid complex also to assess the effects of mechanical, dynamic and physiochemical actions of deterioration and structural deficiency, especially earthquakes and weathering impact on the pyramid structure.
Several tests and laboratory analyzes were carried out to determine the problems of the nature and sustainability of the outer casing stone blocks granite, marble and limestone , filling stone blocks limestone and the structural mortars joining the stone units used in the construction of the three great pyramids in Giza. To investigate the above questions, we selected a total of 45 samples of fallen fragments from different locations around the three pyramids.
The selected samples belong to the back layers and facades and represent typical building material features. Eight thin sections were examined using polarized light microscopy to identify the petrographic and geochemical characteristics of these building materials stones and binding mortars. X-ray diffraction XRD and X-ray florescence XRF probes were conducted to identify slices and ratios of the installation stones and mortar.
With a constant voltage of 40 kV, 30 m and the use of X-ray diffraction PW Engineering characteristics of the studied building materials granite, limestone and structural mortar were achieved. Fifteen cylindrical samples of stones were prepared to determine the petrophysical and geochemical properties. The Cheops, Khephren and Mykerinos pyramids are located in the north-western part of the Giza plateau see Fig.
The altitude above sea level of the rock bases surrounding these monuments is approximately 68 m for Khephren and 62 m for Kheops 60 m at the SE corner , as shown in Fig. Their rock base altitudes are approximately 22 m around the Sphinx and 38 m around Kentkawes [ 9 ]. Geomorphologically, the area under consideration is divided into four distinct units: the plateau, the cliff and the slopes, terraces and the Nile flood plain.
The height of the plateau ranges from 20 m in the northeastern and eastern bottom and The top of the Giza plateau is flat and varies in height from 60 to masl whereas the elevation of the area of the pyramids vary from 60 to 70 masl. The dip angles range from 4 o to 7 o for the eastern part of the plateau near the Sphinx [ 11 ]. The studies show that the monuments of the fourth dynasty of the plateau of Giza are built on a sedimentary sequence with dominant carbonated formations deposited in an epicontinental sea of variable depth.
All the authors agree that these sedimentary layers have the characteristics of the Mokattam formation and Maadi formation, from Middle to Late Eocene age, as shown in Fig. It indicates an increase in groundwater elevation from west to east modified after Sharafeldin et al. The dip of the layers of this monoclinal structure is homogeneous. This monoclinal is affected by hectometric faults with normal dominant and weak throw oriented NW—SE which does not affect the study sites. The weak throw and the orientation of these faults essentially suggest a discrete deformation by synsedimentary normal faults during the Eocene deposition period.
The entire plateau is affected by karstic processes, described by El Aref and Refai [ 14 ] and Dowidar and Abd-Allah [ 11 ], which developed according to the local structural and stratigraphic conditions and led to a particular morphology of stepped terraced escarpments, karst ridges and isolated hills.
These authors relate the development of karst features to Mediterranean climatic conditions [ 9 ]. From the observations made in the boat-pits, at the NE corner of the Cheops pyramid and on the esplanade around the pyramid, we have seen that the rock base of the monument is mainly composed of nummulitic packstone.
It is however possible to establish the presence of original rocky hill, as shown in Fig. The Northern East corner of the great pyramid of Khufu is the visible part of the original hill [ 9 ]. The Northern East corner of the great pyramid. The visible part of the original hill. Boatpit located at the NE of the pyramid showing pyramid base geological series. Petri [ 15 ] observed the rock in the inner proportions at an altitude of 8 m above the level of the scheme. For Eyth [ 16 ] the maximum height of the rock platform is They observed natural rock in the galleries of the pyramid of Cheops and Khephren where the lining of the walls had disappeared [ 9 ].
The study area fractures are found in three major groups heading west—northwest, northwest and northeast. Fractures to the west and northwest are predominant in the northern, western and eastern sides of the Pyramids of Cheops and North of the Pyramids of Chephren [ 9 , 10 , 11 ].
Depending on the depth of the groundwater contour map, there are two groundwater systems in the study area. The first part relates to the groundwater aquifer system and covers the eastern part of the Sphinx area where the depth of the groundwater ranges from 1.
The second system is linked to water. The bearing layers belong to the formation of broken limestone below Sphinx area , where the depth of groundwater ranges from 4 to 7 m below the surface [ 7 ]. According to historical recordings the strong earthquakes and seismic events that have stuck the Giza area induced small or medium damages and structural deficiency to the pyramids complex.
Up to the end of the ninth century the secular number of reported earthquakes fluctuates between zero and three. A relatively high number eight of earthquakes has been reported in the tenth century.
The reported earthquakes reach their highest number 17 in the nineteenth century [ 18 ]. The Question: What is the reason for the proven resistance of the monuments to the seismic events of the past? The instrumental seismicity map indicates that the pyramids site is characterized by very low seismicity setting [ 19 ].
The site selection and the geological properties of the area, being away from seismic effects, floods and groundwater levels, the stability of the geometric form of the pyramid, the solidity of the structural engineering and precision of execution arguably are the reasons why the Great Pyramids of Giza are the only survivors of the seven wonders of the ancient world. Also, the isoseismal intensity contour map reflected that the pyramid site has not been affected by intensity value more than VI on Mercalli scale.
The sedimentary layers where the pyramids were considered a suitable foundation that can safely support the massive rock structure.
Also the spectrum acceleration coefficient and force in the rock Formations are much lower than the spectrum acceleration Coefficient and larger force in the soft and medium soils in particular the clay soil as shown in Fig. Note: soil type coefficient should be examined for the top 30 m of soil or rock Formations layer. Also the ground accelerations are strongly modified by the soil conditions.
Rock sites will have high frequency shaking, while on soft soil sites high frequencies short period will be reduced or filtered out, but low frequencies will be amplified as shown in Fig. The construction details, where the rock keys were used to stabilize the slope against slippage in the Great Pyramid very functional especially during earthquakes.
It is amazing to note that the maximum static stress under the Greater Pyramids is about kPa; yet this huge stress value did not entail any observed or likely foundation failure bearing capacity or excessive settlement.
Show that the builders had taken into consideration the likelihood of seismic loading. Founding of the monuments for the most part on solid rock and good quality of construction of the foundations favour their good anti seismic behavior.
The Pyramidal shape represents an extraordinary advantage, since the pyramid is the most earthquake-resistant structure possible, even more than the domes. For the construction details; several layers of smoothed stones without any mortars or sticky materials between them actually form a kind of base isolation for the foundations, where some flat small stones like pillow were laid to absorb the first shock of earthquake force on the pre-prepared soil under foundations.
Some big stones layers were put over these small stones. The pyramid shaped building is suitable in earthquake prone area due to its higher stiffness and less displacement. The only earthquake that affected the pyramids was in the 14th century on August 8, Later, explorers reported massive piles of rubble at the base of the pyramids left over from the continuing collapse of the casing stones which were subsequently cleared away during continuing excavations of the site.
Nevertheless, many of the outer casing stones around the base of the Khufu Pyramid can be seen today in site, displaying the same workmanship and precision as has been reported for centuries [ 19 ]. Arabic sources reported that this earthquake was the strongest in Egypt, particularly in Alexandria. In Cairo, almost all houses suffered some damage and many large public buildings collapsed.
The earthquake caused panic, and women run into the streets without their veils. Minarets of the mosques of Cairo were particularly affected. In Alexandria, many houses were ruined and killed a number of peoples. The lighthouse was shattered and its top collapsed. The damage extended to Southern Egypt up to Qus. This earthquake was placed by Sieberg to Faiyum, south of Cairo because of the severe damage in Middle Egypt.
It was also reported that this earthquake caused large-scale damage in Rhodes and Crete. Ambraseys [ 23 ] placed its epicenter in the Mediterranean Sea as As-Souty mentioned that the advance of sea submerged half of Alexandria. According to Arabic sources e. El-Maqrizy; As-Souty aftershocks continued during 3 weeks [ 18 ]. Recently the present area is near to relatively active earthquake area to the west of downtown Cairo.
In that area, the most destructive event in recent history of Egypt took place in October 12th, The epicentral distance is only about 30 km. Damage report after that earthquake showed that great pyramids at Giza were severely damaged, and few years later a restoration plan was inaugurated to save the pyramids from more damage and instability problems.
In addition, other earthquake activities are also observed at east Cairo, like Aqaba earthquake in But Dahshour seismic zone constitutes the epicenter of the 12th October Cairo earthquake, and other seismic activity area produced earthquakes with magnitudes seldom reaching a magnitude of 5.
However, due to their proximity from the dense population Cairo metropolitan, such earthquakes were widely felt in greater Cairo area. The seismic zone at Dahshour is only few kilometers from the pyramids complex.
The epicentral distance between Cairo earthquake and pyramids is few kilometers only. This proximity indicates that Dahshour seismic zone might have the highest effect especially at short periods. Most of the typical land failure effects were as extensive as soil liquefaction [ 24 ]. Giza Governorate was exposed to liquids during the 12 October earthquake [ 25 ]. Soil liquefaction has been reported in Giza.
Since this is the last major earthquake affecting the monument, it is possible to assume that the present deformed form and the cracking of the inner chambers and the inner and outer stone layers [ 26 , 27 , 28 , 29 ].
According to the Egyptian newspaper Al-Ahram in 13 October , several small outer casing blocks on the top of the great pyramid and supporting panels fell down during the Dahshuor earthquake It is important to note that after the first earthquake, permanent distortions and therefore moments of permanent curvature remain, so that global behavior, even in the case of low-level earthquakes, becomes weaker and weaker.
The structure is weakened after earthquakes between the blocks and deformations of the exits and pressure in the walls; from this point of view, the current situation is worse than in the past, as shown in Fig. The increasing weakness of the structure after earthquake causing the friction and sliding between the casings and filling blocks.
Show extremely slow degradation process which affected the backing stone blocks of the great pyramid, many blocks were detached. The outer casing stone blocks fell down completely in strong earthquake.
The increasing weakness of the structure after earthquake causing the friction and sliding between the facing and backing blocks. After the earthquake, the Giza pyramids remained deserted and thus suffered a gradual deterioration. Attention initially focused on the lateral boundaries of the remaining facades, where discontinuity and consequently the disappearance of peripheral stress led to a very disadvantageous situation, exacerbated by the dynamics that affected the current boundaries of the areas at risk.
Some cracks affect specific elements such as thresholds for openings, doors and foundation stones, as shown in Fig. Cracking of backing limestone blocks due to the overloading and material decay and strength regression, which affected the great pyramid stability. The honey comb differential weathering aspects are obvious on the surfaces of backing limestone blocks. The outer facing limestone blocks are missed completely.
Alveolization develops her as cavities illustrating a combination of honeycombs and alignment following the natural bedding planes of the limestone. It is difficult to determine the actual degree of stability. Despite this uncertainty, the state of internal pressure of the structure, on the contrary, is well defined. Loss of balance cannot occur during the adjustment. This is the correct aspect of the behavior of building structures that can explain the great durability and longevity of many historic buildings.
The old builders were not Civil engineers. There is something unique in the behavior of construction structures. This is due to the mechanical construction response, and differs significantly from those shown by the usual flexible materials. The difference is due to the low tensile strength of the construction and to the different response of the construction in stresses [ 30 ].
The pyramids were severely damaged on the surface of lower-level stone walls due to long-term static and dynamic actions, extensive cracks in walls caused mainly by settlements, and only because of seismic loads while the foundation stone sites were specifically removed.
The climatic conditions in the study area are semi-arid; warm in winter with little rain and hot to dry in summer.
The climate is characterized by the following parameters. With regard to precipitation, the average annual rainfall does not exceed 25 mm, which is generally rare throughout the year, sometimes occurring in the form of sudden and short showers associated with wind.
For winds, the prevailing wind blows are from the northwest and the monsoon known as Khamasin from the southwest and south. The great pyramids at Giza and have been threatened by rising groundwater levels caused by water infiltration from the suburbs.
Irrigation canals, mass urbanization surrounding GPP, as shown in Fig. Two regional aquifers are located behind the Sphinx statue with a water level at a depth of 1.
The recharge of the aquifer underneath the Sphinx area occurred mainly through diversion of the water network and overall urbanization. The shallow water table elevation at Nazlet El-Samman village reaches 16—17 m and might recharge the aquifer below the Sphinx and Valley Temple, which is considered a severe hazard on the site [ 7 ].
There is deterioration in many parts of the three pyramids, associated with the aging of materials and the impact of aerial and ground water attack, and extreme stresses and cracks have accelerated the related phenomena, as shown in Fig. Many blocks was detached and are hanging. Also represents the extremely slow degradation process which affected the backing limestone blocks of the Mykerinos, pyramid.
The scattering of the granite facing blocks around the pyramid area is obvious. The pyramids stones are characterized by minute cracks, thin and superficial fractures, gaps in the stone veneer, separate stone layers and large gaps below the surficial hard crust. The backing limestone of the three pyramids are characterized by deep and hollow pits on the surface crust.
They are very thin and are based only on a few points. Some parts have lost their shell, and for this reason, large parts are characterized by strong separation. A severe phenomenon is the separation and peeling of the limestone layer due to the capillary rising of ground water, as shown in Fig.
The backing limestone blocks characterized by weak cementation and adhesion due to the presence of small cracks, or pores, of secondary origin resulting from salt weathering. Our analysis showed that the poor state of conservation of the three pyramids can be attributed to two main factors: internal or intrinsic causes, related to the characteristics of the fossil limestone itself e.
While the latter began the process of weathering on limestone blocks, the development and increase of this process is due to lack of cohesion in limestone cement. In fact, the very poor state of maintaining interior walls is due to several internal factors, as in the past, are strictly interconnected. On the other hand, external causes are associated with daily-acute environmental factors Seasonal thermal changes, solar radiation, wind direction and density—work in synergy with the internal causes of limestone degradation.
The most obvious and most common phenomenon is peeling or lids due to the capillary rising of ground water, specific both on the surface, in the form of high elevated chips, deeper parts, with thick detachable layers of limestone blocks. The layer is associated with temperature changes that cause the expansion and contraction cycles of the material, resulting in strong mechanical pressures.
Cracking within crystals is also very common in the fragile deformation of posterior limestone blocks characterized by high gaps. Means within crystals not between crystals. In highly penetrating stones, pressure builds up through the grain—the grain contact becomes large because the forces spread over very small areas stress is the strength of each area , making it easily breakable internally than if porosity is small or non-existent.
Moreover, the behavior of building materials under weathering conditions is predicted by the design of the element and constructive elements. On the other hand, there are some specific weathering forms that affect different granite blocks depending on the surrounding environmental conditions such as red crusts that dominate the case study of aggressive alternative drying and urination cycles, as well as other chemically or biologically related degradation factors for the weathering rates of silicate minerals.
Thus, it can be emphasized that the particular weathering model that characterizes our effects is due to all these factors and associated mechanisms; they consist mainly of complex types of iron oxide-dyed clay minerals. All these factors above require some conservation measures to protect the monuments through various scientific strategic plans containing many preventive and multiple measures.
The pyramids used to be cased. The backing limestone blocks of Chephren pyramid was covered and cased with fine limestone blocks, also the stone cap now remain on the top of the Chephren pyramid. The Mykerinos pyramid was covered and cased with granite facing blocks were quarried and imported from Aswan quarry, km from Cairo. Many facing blocks were taken and reused for the buildings of many Coptic and Islamic monuments in Cairo city, revealing the Fossiliferous limestone backing blocks.
Having this fact, and investigating the formation of the stones of the building material of the pyramid and the ground surface where pyramids were built, one could easily find that the former one was chosen from the upper stratum of Eocenean site while the latter one is the original lower dense stratum of the Eocenean which was used as a base for the structure, as shown in Fig.
By mentioning that, the sum of masses of the pyramids almost reached That was the net weight of the blocks but, if we consider the wasted ruble resulted from shaping the blocks that number could easily have been doubled i.
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