The relationships were studied between wave velocities, fracture frequency, aperture, moisture content, contact pressure at joints and so on, underground at 104 tunneling sites, on several sites at the ground surface, and in laboratory tests. By considering 'fracture frequency' as the main parameter, the practical relationship between seismic behavior and mechanical properties of rock mass has been established. In general the velocity ratio k, defined by the ratio of p-wave veolocity in-situ or through a cracked model to that of intact rock, and fracture frequency n, defined by the number of joints per meter, can be expressed by an equation n = 5.0/squares-4.0. Also an aperture wider than 1 mm and a decrease of contact pressure to less than 3 mpa markedly influence the seismic behavior of the rock mass. The number of the covering abstract of the congress is TRIS no. 385148. (Author/TRRL)
The Great Sphinx-Giza, Egypt was carved out of Middle Eocene limestone formations. The upper part of the statue, including the neck and the head, consists of soft and marly formations (named Maadi Formation). They are highly porous and cavernous showing the evidence of having been greatly affected by water erosion. At present, the Great Sphinx as one of the most important World Heritages is being seriously subjected to aggressive deterioration of limestone members.Since it was not possible to employ any specimen sampled from the immediate site of the Sphinx, it was tried to investigate the process of deterioration of marly limestone in terms of Mokkatam Limestone (called Pyramid Stone) which is considered to be a little older than Maadi Formation. In the present study the process of recrystallization of salt substance on limestone surface and the transportation of salt and water through micro-pores were observed for the period of three months. The electron microscopic scanning was used to illustrate the pore-size, pore distribution and recrystallization of salt. The same test as described in this paper is recommended to be applied to the Maadi Formation for the feasibility study on the preservation of the Great Sphinx.
Unfrozen water content (UWC), which affects the mechanical behavior of frozen soil, was investigated over a continuous temperature range using an isothermal adiabatic calorimeter. The employed soil materials were fine sand, clay and a mixture of fine sand and clay. Water, with or without NaCl, was added to the soil materials. Specimens were obtained by freezing the saturated soils rapidly. The UWC increased with salt concentration and content of fine soil particles. A temperature rise increased the UWC in all frozen soils. A rapid increase in UWC was observed around the eutectic point of saline frozen sand. However, the rapid increase was not observed for saline frozen clay. Total UWC was divided into UWC in brine and absorbed UWC. It was found that the UWC in brine decreases with the content of fine soil particles. Then, the flexural strength of frozen soils was examined for various characteristics of UWC. The dependence of flexural strength on salt concentration was agreement with the dependence on UWC in brine, and the dependence of flexural strength on the content of fine soil particles was in agreement with the dependence on absorbed UWC. The flexural strength of frozen soils, including those containing both salt and fine soil particles, was not determined by the total UWC, but predominantly by UWC in brine.
Mogao Grottos are located at the eastern foot of the Mingsha Dunes, 25km southeast of Dunhuang town. It faces east toward Sanwei Mountain, one range of Qilian Mountains, and in front of it Daquan River runs.The caves were excavated into the cliff on the west bank of the Daquan River. The stratum in which the caves were excavated is the alluvial and pluvial Jiuquan conglomerate in which there is argillaceous and calcareous cementation. The wall paintings in the caves are subject to the severe deterioration generated by recrystallization of salt. It relates with the movement of water/moisture in rock formation. The basement of Mogao Area consists of granite and gneiss formed in the Pre-Cambrian Age. Through the satellite image analysis and geological survey, it has been clarified that the movement of ground water is governed by the fault system and the geographical nature is specified by the aggressive tectonic movement from the south.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
