Evaluation of Pole-dipole technique (Bristow's method) to detect the dimension of K-3 cave in Haditha area -west Iraq- Case study

2020

eijs

The 2D resistivity imaging technique was applied in an engineering study for the investigation of subsurface weakness zones within University of Anbar, western Iraq. The survey was carried out using Dipole-dipole array with an n-factor of 6 and a-spacing values of 2 m and 5 m. The inverse models of the 2D electrical imaging clearly show the resistivity contrast between the anomalous parts of the weakness zones and the background resistivity distribution. The thickness and shape of the subsurface weakness zones were well defined from the 2D imaging using Dipole-dipole array of 2 m a-spacing. The thickness of the weakness zone ranges between 9.5 m to 11.5 m. Whereas the Dipole-dipole array with a-spacing of 5 m and n-factor of 6 allocated the geoelectrical stratigraphic layers sequence in low-accuracy of weakness zones, but deeper than the inverse model of 2 m a-spacing. This survey was made to explain the correlation between the weakness zone and the deeper layers in the study area. It points out that the deeper layers were not affected in the weakness zones. The inverse model was produced using the Standard Least-Squares Inversion Method and the Robust Inversion Model Constraints Method. The first method had a gradational boundary of the weakness zones and the second had sharper and straighter boundaries of fractures and voids within the weakness zones.

Section: Introductionmentioning

confidence: 99%

Application of the Electrical Resistivity Method for Site Investigation in University of Anbar, Ar-Ramadi City, Western Iraq

Salman

Thabit

2020

eijs

“…Inverted 3D models have got them exposed from standard least-squares meth0d and r0bust constrain method at Um El-Githoaa cave sh0wed horiz0ntal slices of the 3D resistivity distribution with depth. [19] applied Graphical Bristow's method above K-3 cavity to evaluate the meth0d to image a relatively large natural cavity. The data interpretations detect the cavity el0ngate along W-E traverse of ab0ut 58.6m with an err0r less than 3% in depth and 2% in height.…”

Section: Introductionmentioning

confidence: 99%

Detection of Haqlaniyah cave within carbonate stratigraphic sequence rocks using 2D resistivity imaging technique, Haditha, western Iraq

Al-jibouri

Al-Halboosi

IOP Conf. Ser.: Earth Environ. Sci.

2022

The western desert of Iraq is characterized by a widespread karst phenomenon and caves. The study area is a site for the establishment of a primary school inAl- Haqlanighah village Haditha area, during leveling the land with a bulldozer, the ground collapsed, causing a hole with a diameter of up to two meters. Two-dimensional resistivity imaging has been applied to detect the depth and extent of the subsurface cave within carbonate rocks and along two cross-image lines in the array of Dipole-dipole and an electrode distance of 5 meters, each length of 105m. 2D Dipole-dipole imaging technique is obtained the inverse models which shows the resistivity variation between the anomalous of background resistivity of rocks and part of cavity is about 750:100 Ω.m. These models showed that the depth 11m at the cavity operator to the roof of cavity. While the actual depth at same location of this cavity measured of 11.35m approximately. The results of this study showed that the extension of the cave along the first track is 52 meters in a direction of west-east, 11 meters depth to the ceiling of the cave, 31-35 meters to the bottom of the cave. While the extension of this cave along the second track is 20 meters in a direction south-north, and the depth to the ceiling of the cave is 12 meters and 32-34 meters to the bottom of the cave. The stratigraphic succession of the study area, starting from bottom withAnah Formation, overlain by unconformity brecciated bed, ranging from 6 to 30m meters in thickness, followed by Euphrates Formation in the top. The unconformity layer is less cohesive than the rocks beneath and above it. So it was the best area for the caves to be formed as a result of dissolving its rocks by leaking rain water and groundwater. Therefore, it must be a pre-engineering preparation before starting any urban construction of the population in the study area or adjacent areas to avoid risks.

“…The Dipole-dipole array is applied again along a traverse in Haditha region above WadhahaShamut cavity. (Abed, 2015) applied the Graphite Bristow method over the K-3 cavity to evaluate the method of depicting a relatively large natural cavity. The result of the extension of the cave is about 58.6 m and depth to the cavity bottom of 33.5 m, with an error of no more than 3% in depth and 2% in height.…”

Section: Introductionmentioning

confidence: 99%

Description of The Karst Phenomena Spreading Along Stratified Sequence in The Western Desert of Iraq

Al-Hetty

Al-jibouri

2021

IGJ

The study focused on two important sites containing many caves sites located in the west of Al Anbar Governorate. The first site is Um El-Githoaa cavity in Hit region, a cave or trunks was chosen to show the aesthetic of this cave in terms of its shape and dimensions. The maximum diameter is 22.1m, while the perpendicular diameter is 18.5m. It is a dome shape and the height of its roof reaches about 2m located in the stratigraphic sequence falls within the massive gypsum, Fatha Formation (Middle Miocene). Geoelectrical exploration was chosen on the southern side of the cave to check whether the sinkholes scattered in the area are connected to subsurface caves or not. Using a Dipole-dipole array was chosen along a traverse, shown there are three sub-surface caves. This indicates that these phenomena are widespread in the region. The second location is Haditha, Barwana Village which was chosen to study where the cave is located in unconformity breccia zone between Anah Formation (Upper Oligocene- Lower Miocene) and Euphrates Formation (Lower Miocene- Middle Miocene). Barwana cave extends to the north 30 m and then tends to the west extend about 1 km within fragile breccia layer with incoherent components and ends with a small opening at the Euphrates River. This phenomenon was not present in the hard gypsum rocks in the Hit region, it was observed to have a large oval shape