**Abstract**

The Greek-Roman rock-cut tombs at Alexandria, Egypt, were excavated mainly in the calcarenitic limestone formations and show varying degrees of damage of rock pillars and ceilings. In order to understand the long-term rock mass behaviour in selected tombs and its impact on past failures and current stability, uniaxial and triaxial Creep tests and rock mass quality assessments had been carried out. Creep behavior of rock plays an important role in underground works, especially for archeological structures subjected to large initial stresses. These conditions yield nonreversible deviatoric creep strains that develop during time at constant stress. In order to describe the time-dependent deformation, various approaches have been established based on analytical, empirical, and numerical methods. Our analyses show that the Roman tombs at Alexandria have been cut into poor quality rock masses. Rock failures of ceilings and pillars were frequently facilitated by local, unfavourably oriented persistent discontinuities, such as tension cracks and joints. Other failures were related to the disintegration of calcarenitic and oolitic limestones. Our data suggest that, in Roman age monumental tomb construction, lowstrength rock masses resulted in modifications of the planned tomb design in order to minimise the risk of rock falls and to prevent collapses.

**Keywords:** Roman rock-cut tombs, geotechnical assessment, creep tests, calcarenitic limestone, oolitic limestone, rock mass rating, tomb construction

## **1. Introduction**

Creep is an irreversible ductile time-dependent deformation, without fracture where deformation does not occur suddenly when applying stress as opposed to brittle fracture. Instead, strain accumulates as a result of long-term stress [1–4]. This behavior usually distinguishes weak rocks such as rock salt, shale, buttocks, venetian, silt, and sandstone. Rock creep behavior has been widely discussed in the literature, based on experimental results from laboratory or field investigations, foundational modeling, and numerical analyses. The main objective of this chapter is to focus on appropriate methodologies for determining the creep behavior of soft/ weak intact rocks through laboratory experimental analysis and critical evaluation of available rheological models to explain creep behavior [5–9].

Creeping in fragile hard rocks is rare because the deformation rate is too slow. Solid rocks exhibit a creep behavior noticeably only at elevated temperatures and pressures generally not encountered in engineering structures. Soft rocks on the other hand mostly creep at room temperature, atmospheric pressure, and the range of deviating stress typically encountered in engineering structures [10–12].

As we know, creeping rocks have a significant effect on the long-term stability of the rocks and the surrounding surface [13–16]. For broken rocks, porosity is the primary determinant of creep characteristics, but in the existing literature, the stress rate was mainly used to describe the creeping properties of broken rocks. For example, Wang [17, 18] carried out numerical simulations on the process of creeping damage to the road surrounding the rock under high pressure, and Zhu and Ye discussed the law of creep affected by water content by comparing the results of the rock creep test under dry condition and in saturation. Zhang and Luo [19] studied the properties of creeping rocks under different stress levels. Liu et al. [20] performed triaxial creep tests on coal and rock by step loading method. Zhang and Luo [19] examined the creeping test of marble and soft rock separately; Parkin [21] used a pressure meter to study the rheological properties of granular materials. Shen and Zhao [22] proposed a model for three parameters of creeping rock filling through rheological experiments on limestone. Zheng and Ding proposed a creep model to rocks of nine parameters and obtained parameter indexes through tests. Guo et al. [23] proposed a modified three-parameter rheological model for coarse-grained materials. Wang [24] and Liu et al. [25] summarized the rheological state of coarse-grained materials and noted that experimental studies on granular materials were insufficient.

They suggested that it is necessary to study the mechanism of partial deformation of coarse granular materials given the effect of the scale for internal testing.

Understanding the mechanisms of deterioration of the calcarenite rock structures in which the Greco-Roman monuments are excavated requires a comprehensive study of the mechanical behavior and engineering properties of the calcarenite rocks. In addition to geological and geomorphological concerns, numerous investigations have been conducted on rock degradation and disintegration. As the areas are an open museum and attractive places for tourists, sampling can only take place in a limited number of locations with official permission. For this purpose, cylindrical samples with a diameter of 42–44 mm and a height of 90–100 mm, prepared using a basic drilling machine and some blocks collected from archeological sites under investigation (catacomb from Kom El-Shoqafa, El-Shatby tombs, and tombs of Mustafa Kamel), as shown in **Figure 1** illustrates the physical, short, and longterm mechanical properties of calcarenitic rocks in the laboratory, a number of samples prepared from these blocks have been used for testing, and the limitations of the number of blocks have been overcome by determining the topical properties of the rocks through hammer tests. Schmidt, pictorial geographic investigations and classification of the rocky hill in some outcrops and in some rock structures where testing was permitted.

The purpose of this research is to make recommendations on the strengthening and safety of archeological underground structures under long- and short-term loading. For this purpose, a set of experimental tests and advanced digital analyses had been performed.

Calcarenitic rocks and other type of fine limestone (under investigations) are porous rocks with complex behavior [26–28]. Two major mechanisms can be identified to distort types of rock properties, depending on conditions in-situ stress: (1) the prevalence of fracture, associated with volumetric expansion and fragile

*Uniaxial and Triaxial Creep Performance of Calcarenitic and Sandy Oolitic Limestone…*

*DOI: http://dx.doi.org/10.5772/intechopen.91720*

*Underground monuments (Catacombs) in Alexandria, (present conditions).*

**Figure 1.**

**15**

*Uniaxial and Triaxial Creep Performance of Calcarenitic and Sandy Oolitic Limestone… DOI: http://dx.doi.org/10.5772/intechopen.91720*

#### **Figure 1.**

literature, based on experimental results from laboratory or field investigations, foundational modeling, and numerical analyses. The main objective of this chapter is to focus on appropriate methodologies for determining the creep behavior of soft/ weak intact rocks through laboratory experimental analysis and critical evaluation

*Geotechnical Engineering - Advances in Soil Mechanics and Foundation Engineering*

Creeping in fragile hard rocks is rare because the deformation rate is too slow. Solid rocks exhibit a creep behavior noticeably only at elevated temperatures and pressures generally not encountered in engineering structures. Soft rocks on the other hand mostly creep at room temperature, atmospheric pressure, and the range

As we know, creeping rocks have a significant effect on the long-term stability of the rocks and the surrounding surface [13–16]. For broken rocks, porosity is the primary determinant of creep characteristics, but in the existing literature, the stress rate was mainly used to describe the creeping properties of broken rocks. For example, Wang [17, 18] carried out numerical simulations on the process of creeping damage to the road surrounding the rock under high pressure, and Zhu and Ye discussed the law of creep affected by water content by comparing the results of the rock creep test under dry condition and in saturation. Zhang and Luo [19] studied the properties of creeping rocks under different stress levels. Liu et al. [20] performed triaxial creep tests on coal and rock by step loading method. Zhang and Luo [19] examined the creeping test of marble and soft rock separately; Parkin [21] used a pressure meter to study the rheological properties of granular materials. Shen and Zhao [22] proposed a model for three parameters of creeping rock filling through rheological experiments on limestone. Zheng and Ding proposed a creep model to rocks of nine parameters and obtained parameter indexes through tests. Guo et al. [23] proposed a modified three-parameter rheological model for coarse-grained materials. Wang [24] and Liu et al. [25] summarized the rheological state of coarse-grained materials and noted that experimental

They suggested that it is necessary to study the mechanism of partial deformation of coarse granular materials given the effect of the scale for internal testing. Understanding the mechanisms of deterioration of the calcarenite rock structures in which the Greco-Roman monuments are excavated requires a comprehensive study of the mechanical behavior and engineering properties of the calcarenite rocks. In addition to geological and geomorphological concerns, numerous investigations have been conducted on rock degradation and disintegration. As the areas are an open museum and attractive places for tourists, sampling can only take place in a limited number of locations with official permission. For this purpose, cylindrical samples with a diameter of 42–44 mm and a height of 90–100 mm, prepared using a basic drilling machine and some blocks collected from archeological sites under investigation (catacomb from Kom El-Shoqafa, El-Shatby tombs, and tombs of Mustafa Kamel), as shown in **Figure 1** illustrates the physical, short, and longterm mechanical properties of calcarenitic rocks in the laboratory, a number of samples prepared from these blocks have been used for testing, and the limitations of the number of blocks have been overcome by determining the topical properties of the rocks through hammer tests. Schmidt, pictorial geographic investigations and classification of the rocky hill in some outcrops and in some rock structures where

The purpose of this research is to make recommendations on the strengthening and safety of archeological underground structures under long- and short-term loading. For this purpose, a set of experimental tests and advanced digital analyses

of deviating stress typically encountered in engineering structures [10–12].

of available rheological models to explain creep behavior [5–9].

studies on granular materials were insufficient.

testing was permitted.

had been performed.

**14**

*Underground monuments (Catacombs) in Alexandria, (present conditions).*

Calcarenitic rocks and other type of fine limestone (under investigations) are porous rocks with complex behavior [26–28]. Two major mechanisms can be identified to distort types of rock properties, depending on conditions in-situ stress: (1) the prevalence of fracture, associated with volumetric expansion and fragile

behavior, which is predominant in compressive stress paths in the absence of low confined pressure, or (2) pore breakdown, which dominates high-stress conditions, producing plastic deformations and large contracting [29].

The high fossil content, mainly due to the shells of necrosis and some mollusks, leads to structural heterogeneity, which is reflected in the variance of mechanical properties and weaknesses in the conclusion of experimental results [13].

There is no generally accepted theory of fragile rock strength based on examination of the process of formation of microcracks and deformation, and the establishment of the initiation and development of stress-induced fractures in EDZ is therefore a major concern.

Some of the main concerns related to the stability of underground structures in soft rocks include the effects of potential land disturbances through the method of drilling and reallocation of pressures at the site surrounding the excavations [30–35]. Each of these factors relates to the initiation and spread of fragile fractures and the extent of the troubled drilling area (EDZ), which can adversely affect the stability of the drilling boundaries and can increase the permeability of host rocks to the near field. In structural and tectonic geology, experimental rock deformation is important in determining the evolution of natural structures and tectonic features [36, 37].

Great effort has been made toward understanding the fragile fracture processes and mechanisms. Much of this focus extended to laboratory tests and quantification/ measurement of fragile fracture thresholds [7, 38]. Among these, damaged thresholds marked by the onset of expansion, which is the reflection point of the volumetric pressure curve, are particularly important because many studies have linked the threshold to the spread of unstable fracture in fragile rocks [7]. The unstable crack spreading corresponds to the point where the reproduction process is controlled between the applied stress and the speed of crack growth. Under these circumstances, the crack will continue to spread until failure even if the applied load stops and remains stable. As such, Martin and Chandler and Read et al. equated the threshold of damage caused by cracking and the long-term on-site strength of fragile rocks.

been connected to fresh Nile river flows and sea water sources and has been both at and below mean sea level. Lake Maryout and Delta had varied depositional environment, including "silt and clay deposits with some organics (lagoonal deposit)"; "sand and silt deposits (Nile River deposits); "sand deposits (beach and littoral deposits"). The basement rock unit is Miocene (6–25 million years old) and older carbonate formations that comprise the Egyptian plateau. Above the Miocene sedimentary rocks are Plio-Pleistocene age (less than 6 million years old) sediments consisting of alternating beds of shale, limestone, sandstone, silt, and

*Uniaxial and Triaxial Creep Performance of Calcarenitic and Sandy Oolitic Limestone…*

The Plio-Pleistocene sediments form a series of ridge and trough that are approximately parallel to the Mediterranean coastline in the vicinity of the catacomb site. Most of the city of Alexandria rests on one of these topographic ridges while behind the ridge, Lake Maryout is in a trough. The near surface limestone deposits, which are commonly encountered in the Alexandrian ridge, are cemented

The catacombs of Alexandria show some clear indications of yield and partial collapse in several locations, as defined in the honeycomb weathering, the contour scaling and spalling of the stone surface, the disintegration of building materials, and the wet surfaces of rocky meals especially for semi-protected parts of the excavation; also, we observe salt flowering and yellow staining of yellow iron in

Structural damage is obvious like the wall cracking, the thinning out of rock pillars, disintegration and degradation of the walls surfaces, the partial collapse of some parts of the roofs and walls, and the peeling of rocks, especially in the roof of narrow corridors found in the deepest parts and mass waste from the ceiling and walls.

In conclusion, the current state of conservation of the great catacombs at Kom

El-Shoqafa, the best-known and most famous testimony of the culture of the

funerary architecture of Alexandria, is now at its most deteriorating.

calcareous sand.

**Figure 2.**

*The limestone outcrop at the catacombs of Kom El-Shoqafa.*

*DOI: http://dx.doi.org/10.5772/intechopen.91720*

marine sand.

many wall parts.

**17**

**3. State of preservation**

Thus, the identification of these processes and associated mechanisms is essential in predicting both the strength of soft rocks in the short and long term. This research focuses on these processes by presenting the results of many short- and long-term laboratory tests.

In general, the spread of cracks can be equated with the irreversible destruction of molecular cohesion along the path of the crack generated. In this sense, the miniature crushing process "damages" the rock material. Due to the multiplication of the number of reproductive fractures, the damage can be considered to be cumulative and can be associated with a perceived lack of elastic stiffness and the strength of material cohesion.

In this work, we highlighted some important characteristics of the geotechnical behavior of structured soft rocks and showed that these properties are very common in many natural rocks. Based on these concepts, research into soil/rocky transition material has intensified in the last two decades [39].

#### **2. Geological and tectonic setting**

The Roman underground tombs in Alexandria are located on the northern edge of the "Nile Delta geomorphic province, c. 1.30 km north of the Lake Maryout and 1.42 km south of the Mediterranean Sea shoreline, as shown in **Figure 2**". Since Pleistocene time, within the last 1 million years, Lake Maryout has intermittently

*Uniaxial and Triaxial Creep Performance of Calcarenitic and Sandy Oolitic Limestone… DOI: http://dx.doi.org/10.5772/intechopen.91720*

#### **Figure 2.**

behavior, which is predominant in compressive stress paths in the absence of low confined pressure, or (2) pore breakdown, which dominates high-stress conditions,

properties and weaknesses in the conclusion of experimental results [13].

*Geotechnical Engineering - Advances in Soil Mechanics and Foundation Engineering*

The high fossil content, mainly due to the shells of necrosis and some mollusks, leads to structural heterogeneity, which is reflected in the variance of mechanical

There is no generally accepted theory of fragile rock strength based on examination of the process of formation of microcracks and deformation, and the establishment of the initiation and development of stress-induced fractures in EDZ is

Some of the main concerns related to the stability of underground structures in soft rocks include the effects of potential land disturbances through the method of drilling and reallocation of pressures at the site surrounding the excavations [30–35]. Each of these factors relates to the initiation and spread of fragile fractures and the extent of the troubled drilling area (EDZ), which can adversely affect the stability of the drilling boundaries and can increase the permeability of host rocks to the near field. In structural and tectonic geology, experimental rock deformation is important in determining the evolution of natural structures and tectonic features

Great effort has been made toward understanding the fragile fracture processes and mechanisms. Much of this focus extended to laboratory tests and quantification/ measurement of fragile fracture thresholds [7, 38]. Among these, damaged thresholds marked by the onset of expansion, which is the reflection point of the volumetric pressure curve, are particularly important because many studies have linked the threshold to the spread of unstable fracture in fragile rocks [7]. The unstable crack spreading corresponds to the point where the reproduction process is controlled between the applied stress and the speed of crack growth. Under these circumstances, the crack will continue to spread until failure even if the applied load stops and remains stable. As such, Martin and Chandler and Read et al. equated the threshold of damage caused by cracking and the long-term on-site strength of fragile rocks.

Thus, the identification of these processes and associated mechanisms is essential in predicting both the strength of soft rocks in the short and long term. This research focuses on these processes by presenting the results of many short- and

In general, the spread of cracks can be equated with the irreversible destruction

In this work, we highlighted some important characteristics of the geotechnical behavior of structured soft rocks and showed that these properties are very common in many natural rocks. Based on these concepts, research into soil/rocky

The Roman underground tombs in Alexandria are located on the northern edge of the "Nile Delta geomorphic province, c. 1.30 km north of the Lake Maryout and 1.42 km south of the Mediterranean Sea shoreline, as shown in **Figure 2**". Since Pleistocene time, within the last 1 million years, Lake Maryout has intermittently

of molecular cohesion along the path of the crack generated. In this sense, the miniature crushing process "damages" the rock material. Due to the multiplication of the number of reproductive fractures, the damage can be considered to be cumulative and can be associated with a perceived lack of elastic stiffness and the

transition material has intensified in the last two decades [39].

producing plastic deformations and large contracting [29].

therefore a major concern.

long-term laboratory tests.

strength of material cohesion.

**16**

**2. Geological and tectonic setting**

[36, 37].

*The limestone outcrop at the catacombs of Kom El-Shoqafa.*

been connected to fresh Nile river flows and sea water sources and has been both at and below mean sea level. Lake Maryout and Delta had varied depositional environment, including "silt and clay deposits with some organics (lagoonal deposit)"; "sand and silt deposits (Nile River deposits); "sand deposits (beach and littoral deposits"). The basement rock unit is Miocene (6–25 million years old) and older carbonate formations that comprise the Egyptian plateau. Above the Miocene sedimentary rocks are Plio-Pleistocene age (less than 6 million years old) sediments consisting of alternating beds of shale, limestone, sandstone, silt, and calcareous sand.

The Plio-Pleistocene sediments form a series of ridge and trough that are approximately parallel to the Mediterranean coastline in the vicinity of the catacomb site. Most of the city of Alexandria rests on one of these topographic ridges while behind the ridge, Lake Maryout is in a trough. The near surface limestone deposits, which are commonly encountered in the Alexandrian ridge, are cemented marine sand.

### **3. State of preservation**

The catacombs of Alexandria show some clear indications of yield and partial collapse in several locations, as defined in the honeycomb weathering, the contour scaling and spalling of the stone surface, the disintegration of building materials, and the wet surfaces of rocky meals especially for semi-protected parts of the excavation; also, we observe salt flowering and yellow staining of yellow iron in many wall parts.

Structural damage is obvious like the wall cracking, the thinning out of rock pillars, disintegration and degradation of the walls surfaces, the partial collapse of some parts of the roofs and walls, and the peeling of rocks, especially in the roof of narrow corridors found in the deepest parts and mass waste from the ceiling and walls.

In conclusion, the current state of conservation of the great catacombs at Kom El-Shoqafa, the best-known and most famous testimony of the culture of the funerary architecture of Alexandria, is now at its most deteriorating.

Most structural damage is caused by one or a combination of the following factors:

• The gradual weakening of rock materials due to the intrinsic sensitivity of weathering factors, especially the effect of weathering with groundwater and salt thickness of about 1 mm (bedding plane). Optical microscopy and counting points were performed on thin sections of rock samples. The air-dried samples were inoculated with Canada balsam, and the thin sections were then cut perpendicular to the bedding planes. A thin section is observed under parallel light and polarizing light. The following is a detailed analysis of the rock samples collected from the three archeological sites under investigation, rock samples from six collections of El-Shatby with code Nr (SH), five rock samples collected from the tombs of Mustafa Kamel 1 and No. 2 with code Nr (M), and four samples Rock collected from

*Uniaxial and Triaxial Creep Performance of Calcarenitic and Sandy Oolitic Limestone…*

In the internal structure, we can observe the dominant components, which are the cells of the fibers of the stomach, grass, algae, and mother of pearl, mostly with a test wall of microscopic microspheres, while the tests are filled internally with microtomes and microbes (**Figure 3**). Surrounded monocrystalline quartz granules of varying sizes and perimeter of iron oxides have been detected representing the previous presence of K-feldspar grains. Rock and granular materials make up this

(Calcarenite size) 15% of customizations are medium-sized numulite tests filled with prickly calcite. 15% of foraminifers tests with a neomorphic microspar test wall and test chambers are full of neomorphic microspar. 20% of medium size bryoza and algae tests 0.25% small size, monocrystalline, crispy extinction, quartz granules subrounded. 25% medium to small size structure less ooides. Customizations are solidified by isopachous microspar. Porosity is a fit of 20% of the area of the thinsection field, which is reduced by microscopy. Oxidation is observed as red color

The rock texture in these tombs consists of two textures, namely packed stone and

Calcarenite is a bio-soft rock originating from marine sediments, which occurred

Changes in internal structure and metals were analyzed and the most distinctive textures documented on the images. In the internal structure, we can observe the porosity increase of various sizes. In some places, we can find cracks on metal contacts or even inside metals. Generally, significant changes are shown in the cement material; see **Figure 5**. Limestone in this site can be classified into two types

during the overflow and decline of the region in the Ice Age. The calcarenite consists of almost pure calcium carbonate and is applied directly to the limestone

stone. These two types of texture show different proportions and sizes of quartz granules, and different biological plates, especially foraminifer tests. Most Ooides lost their internal structure. Few of them retain their concentric structure. Consolidation of the components of this limestone is represented by isopachous microspar (**Figure 4**). (Calc rud –arenite size) 58% of the assignments are medium in size, thin and micro pigment and less pollutant internal structure. 10% micritic oval. 30% large to small angular size to subrounded, crispy extinction, monocrystalline quartz. 2% plajioclase and microcline crystals. Porosity reached 20% of the area of the thinsection field. The pores are filled with neomorphic microspar. Allochems are

Catacomb of Kom El-Shoqafa code Nr (COM).

**4.1 Catacombs of Kom El-Shoqafa**

*DOI: http://dx.doi.org/10.5772/intechopen.91720*

fossil sand limestone, or cement sand.

**4.2 Mustafa Kamel Necropolis**

surrounded with isopachous microspar.

rock of the Cretaceous.

**4.3 El-Shatby cemetery**

**19**

spots.


### **4. Mineralogical and petrographical studies**

The effort behind thin-section analysis was to provide insight into the closed grains (calcite/sand) and/or theories of overgrowth after precipitation of the large angle of internal friction. Due to the fragile nature of the rocks and plaster layers being excavated, it was necessary to be very careful to make thin sections, which were studied using independent polarized light, electron microscopy (SEM), and stereoscopic observation.

A light-transmitted polarized plane, scanning electron microscopy, and stereoscopic observations were used to determine the interlocking textures and connections between grains and crystals. These contacts rely on differences in solubility due to impurities and differences in bending radius, which lead to the penetration of smaller grains in large grains.

In addition, thin section microscopy was used to help explain the large friction angles associated with the material, limestone/rock.

Miniature petrographic description of stones/rocks for engineering purposes includes the identification of all parameters that cannot be obtained from a comprehensive endoscopic examination of rock samples, such as mineral content, grain size and texture, which have an impact on the mechanical behavior of the rock or rock mass. To ensure proper classification, the first step should be to check the metal composition and rock texture; see **Table 1**. Mineralogy summarizes the three types of soft limestone under investigation. Additional investigations should include analysis of the texture and minerals in the case of highly contrasting rocks, determining the degree of change or weathering, grain size, partial fracture, and porosity.

In sandstone, limestone, and calcarenite samples intact, it is possible to determine with the naked eye an alternative sequence of white and pink bands with a


**Table 1.**

*Mineralogy of the three soft limestone types under investigation.*

*Uniaxial and Triaxial Creep Performance of Calcarenitic and Sandy Oolitic Limestone… DOI: http://dx.doi.org/10.5772/intechopen.91720*

thickness of about 1 mm (bedding plane). Optical microscopy and counting points were performed on thin sections of rock samples. The air-dried samples were inoculated with Canada balsam, and the thin sections were then cut perpendicular to the bedding planes. A thin section is observed under parallel light and polarizing light. The following is a detailed analysis of the rock samples collected from the three archeological sites under investigation, rock samples from six collections of El-Shatby with code Nr (SH), five rock samples collected from the tombs of Mustafa Kamel 1 and No. 2 with code Nr (M), and four samples Rock collected from Catacomb of Kom El-Shoqafa code Nr (COM).

#### **4.1 Catacombs of Kom El-Shoqafa**

Most structural damage is caused by one or a combination of the following

*Geotechnical Engineering - Advances in Soil Mechanics and Foundation Engineering*

• The gradual weakening of rock materials due to the intrinsic sensitivity of

The effort behind thin-section analysis was to provide insight into the closed grains (calcite/sand) and/or theories of overgrowth after precipitation of the large angle of internal friction. Due to the fragile nature of the rocks and plaster layers being excavated, it was necessary to be very careful to make thin sections, which were studied using independent polarized light, electron microscopy (SEM), and

A light-transmitted polarized plane, scanning electron microscopy, and stereoscopic observations were used to determine the interlocking textures and connections between grains and crystals. These contacts rely on differences in solubility due to impurities and differences in bending radius, which lead to the penetration

In addition, thin section microscopy was used to help explain the large friction

**CaCO3 %**

Sandy oolitic limestone (Kom El-Shoqafa) (COM) 47–65 31–23 10–5 12–9 2 Intact Calcarenite (Mustafa Kamel Necropolis) (M) 52–72 28–18 8–3 12–6 3–5

**Quartz SiO2 %**

**Gypsum CaSO4.2H2O %**

53–80 25–20 11–7 11–7 3

**Halite NaCl %**

**Other %**

Miniature petrographic description of stones/rocks for engineering purposes includes the identification of all parameters that cannot be obtained from a comprehensive endoscopic examination of rock samples, such as mineral content, grain size and texture, which have an impact on the mechanical behavior of the rock or rock mass. To ensure proper classification, the first step should be to check the metal composition and rock texture; see **Table 1**. Mineralogy summarizes the three types of soft limestone under investigation. Additional investigations should include analysis of the texture and minerals in the case of highly contrasting rocks, determining the degree of change or weathering, grain size, partial fracture, and porosity. In sandstone, limestone, and calcarenite samples intact, it is possible to determine with the naked eye an alternative sequence of white and pink bands with a

• Earthquake and other man-made dynamic loading

• Permanent deformation of the rock mass

**4. Mineralogical and petrographical studies**

angles associated with the material, limestone/rock.

**Rock type Calcite**

Oolitic intraclastic limestone (El-Shatby Necropolis)

*Mineralogy of the three soft limestone types under investigation.*

(SH)

**Table 1.**

**18**

• Natural wear and tear of materials

• History of construction in the area

stereoscopic observation.

of smaller grains in large grains.

weathering factors, especially the effect of weathering with groundwater and salt

factors:

In the internal structure, we can observe the dominant components, which are the cells of the fibers of the stomach, grass, algae, and mother of pearl, mostly with a test wall of microscopic microspheres, while the tests are filled internally with microtomes and microbes (**Figure 3**). Surrounded monocrystalline quartz granules of varying sizes and perimeter of iron oxides have been detected representing the previous presence of K-feldspar grains. Rock and granular materials make up this fossil sand limestone, or cement sand.

(Calcarenite size) 15% of customizations are medium-sized numulite tests filled with prickly calcite. 15% of foraminifers tests with a neomorphic microspar test wall and test chambers are full of neomorphic microspar. 20% of medium size bryoza and algae tests 0.25% small size, monocrystalline, crispy extinction, quartz granules subrounded. 25% medium to small size structure less ooides. Customizations are solidified by isopachous microspar. Porosity is a fit of 20% of the area of the thinsection field, which is reduced by microscopy. Oxidation is observed as red color spots.

#### **4.2 Mustafa Kamel Necropolis**

The rock texture in these tombs consists of two textures, namely packed stone and stone. These two types of texture show different proportions and sizes of quartz granules, and different biological plates, especially foraminifer tests. Most Ooides lost their internal structure. Few of them retain their concentric structure. Consolidation of the components of this limestone is represented by isopachous microspar (**Figure 4**).

(Calc rud –arenite size) 58% of the assignments are medium in size, thin and micro pigment and less pollutant internal structure. 10% micritic oval. 30% large to small angular size to subrounded, crispy extinction, monocrystalline quartz. 2% plajioclase and microcline crystals. Porosity reached 20% of the area of the thinsection field. The pores are filled with neomorphic microspar. Allochems are surrounded with isopachous microspar.

Calcarenite is a bio-soft rock originating from marine sediments, which occurred during the overflow and decline of the region in the Ice Age. The calcarenite consists of almost pure calcium carbonate and is applied directly to the limestone rock of the Cretaceous.

#### **4.3 El-Shatby cemetery**

Changes in internal structure and metals were analyzed and the most distinctive textures documented on the images. In the internal structure, we can observe the porosity increase of various sizes. In some places, we can find cracks on metal contacts or even inside metals. Generally, significant changes are shown in the cement material; see **Figure 5**. Limestone in this site can be classified into two types

#### **Figure 3.**

*Photomicrograph of fossiliferous sandy oolitic limestone, (a) under parallel polarized light, (b) under cross polarized light (XPL), showing bioclasts of gastropods, foraminifera, algae, and shell debris; most of them are with test wall of neomorphic microspar, filled with micrite and microspar, cracks between and through the minerals are obvious. Catacombs of Kom El-Shoqafa.*

enables the assessment of pore size and distribution in relation to the distribution

*(a, b) Photomicrograph of intact calcarenite under cross polarized light (XPL) showing wackestone (pele-oosparite) texture with drusy sparite, Mustafa Kamel Necropolis (Weathered sample, heterogeneous pore system).*

*Uniaxial and Triaxial Creep Performance of Calcarenitic and Sandy Oolitic Limestone…*

*DOI: http://dx.doi.org/10.5772/intechopen.91720*

Samples can be clearly distinguished from the alveolar portions - the amortized and non-woven parts using thin, unpainted limestone sections that feature a relatively homogeneous pore structure. In contrast to unpainted areas, alveolar flats have a heterogeneous pore structure, for example pores often contain ferric oxides and hydroxides indicating a lower total pore size and higher content of small spots.

**4.4 Comparison between the sound and weathered rock layers**

and formation of the minerals involved.

**Figure 4.**

**21**

of fabric, namely, fossiliferous oolitic intraclasic limestone. These two types of texture are in different proportions of quartz granules, biological panels, ooides, and peloids.

(Callus arinite rod size) 80% of the customizations are medium-sized structure less ooides. 10% large to medium-sized monocrystalline unite extinction, quartz granules subrounded. 5% large polycrystalline, crispy extinction, quartz granules subrounded. Five% of algae and foraminifera are tested with a micritic wall and are filled internally with microscopic grains. Porosity is greatly reduced due to their filling with depressed dwarfs. The new form is observed to worsen from micrite to microspar. The evaluation of thin sections allows the analysis of pore structure and

*Uniaxial and Triaxial Creep Performance of Calcarenitic and Sandy Oolitic Limestone… DOI: http://dx.doi.org/10.5772/intechopen.91720*

**Figure 4.**

of fabric, namely, fossiliferous oolitic intraclasic limestone. These two types of texture are in different proportions of quartz granules, biological panels, ooides,

*Photomicrograph of fossiliferous sandy oolitic limestone, (a) under parallel polarized light, (b) under cross polarized light (XPL), showing bioclasts of gastropods, foraminifera, algae, and shell debris; most of them are with test wall of neomorphic microspar, filled with micrite and microspar, cracks between and through the*

*Geotechnical Engineering - Advances in Soil Mechanics and Foundation Engineering*

(Callus arinite rod size) 80% of the customizations are medium-sized structure less ooides. 10% large to medium-sized monocrystalline unite extinction, quartz granules subrounded. 5% large polycrystalline, crispy extinction, quartz granules subrounded. Five% of algae and foraminifera are tested with a micritic wall and are filled internally with microscopic grains. Porosity is greatly reduced due to their filling with depressed dwarfs. The new form is observed to worsen from micrite to microspar. The evaluation of thin sections allows the analysis of pore structure and

and peloids.

**20**

*minerals are obvious. Catacombs of Kom El-Shoqafa.*

**Figure 3.**

*(a, b) Photomicrograph of intact calcarenite under cross polarized light (XPL) showing wackestone (pele-oosparite) texture with drusy sparite, Mustafa Kamel Necropolis (Weathered sample, heterogeneous pore system).*

enables the assessment of pore size and distribution in relation to the distribution and formation of the minerals involved.

#### **4.4 Comparison between the sound and weathered rock layers**

Samples can be clearly distinguished from the alveolar portions - the amortized and non-woven parts using thin, unpainted limestone sections that feature a relatively homogeneous pore structure. In contrast to unpainted areas, alveolar flats have a heterogeneous pore structure, for example pores often contain ferric oxides and hydroxides indicating a lower total pore size and higher content of small spots.

"plastic deformation." It is a progressive phenomenon initiated at a certain time after excavation at a certain location around the profile and spreading in time into the rock mass. For the long-duration design life of underground structures, the long-term stability of the tunnel must receive major consideration. For this reason, time-dependent deformation behavior of the surrounding rock must be well understood. Neglecting creep effects during deep excavation may lead to incorrect evaluation of deformation and thus may impact on the criteria for selection of

*Uniaxial and Triaxial Creep Performance of Calcarenitic and Sandy Oolitic Limestone…*

Understanding the mechanisms of rock breakdown that have been excavated within ancient monuments requires a thorough study of the mechanical behavior of these rocks, and the importance of the physical and mechanical properties of these

The results of the geotechnical characterization of these rocks will be used in numerical modeling and design of reinforcement measures. For this purpose, a new

Rocks, sample preparation, experimental setup used and the procedure are

An idealized creep curve for rock at constant stress consists of three stages: instantaneous elastic strain followed by primary creep with decreasing creep rate, then steady-state creep with constant creep rate, and finally tertiary creep with increasing creep rate leading to failure. Most of the work on time-dependent strain has been conducted on primary and secondary creep phases only and the tertiary

In this study, the size of the comprehensive laboratory testing program using cylindrical samples with 42-44 mm diameter and height (91–103 mm). Although these rocks do not show distinct layers, the nuclei were extracted from the blocks and their masses in the vertical direction, which was expected to represent the physical properties of these units perpendicular to the layers. However, some samples were also extracted in a vertical direction on the mattress. Some specimens were broken and/or small cracks or cracks appeared on their surfaces. However, in order to achieve reliable assessments, the number of samples was increased as many as possible. Laboratory tests were performed in accordance with the testing procedures proposed ISRM and recommended by ASTM at the Engineering Geology Laboratory, Department of Civil Engineering, University of Aristotle Thessaloniki,

Laboratory studies (experimental examination) were performed on surface rock

samples and prepared surfaces. The basic mechanical testing of the laboratory includes the behavior of deformation to failure under uniaxial and triaxial compression and we offer a complete creeping rock characterization conducted during the past 2 years from a series of isotropic and isotropic compression tests conducted in the inventory of various stresses, viscosity behavior was determined by following a procedure, the multi-step download, which emphasizes the transit

rocks to understand the phenomena of instability.

phase has not been investigated in appreciable detail.

laboratory testing program will be launched.

*DOI: http://dx.doi.org/10.5772/intechopen.91720*

proper design.

briefly described below.

**5.2 Laboratory test specimens**

**5.1 Types of creep**

Greece.

creep side.

**23**

**5.3 Laboratory tests**

**Figure 5.** *(a, b) Photomicrograph of fossiliferous oolitic intraclastic limestone thin section under cross-polarized light (XPL) showing subrounded monocrystalline quartz grains (QTZ) and porous region, El-Shatby Necropolis.*

Data from microscopic polarization and electron microscopy experiments show that oxygen clarity of NaCl crystals is strongly influenced by the rate and volume of moisture changes, and how they shrink with changes in crystal size.
