Exam No. 3 2018.pdi -Adobe Acrobat Reader DC File EditView Windaw Help Home Tool

Question

Exam No. 3 2018.pdi -Adobe Acrobat Reader DC File EditView Windaw Help Home Tools Exam No. 3 2018 p... * Sign In Export PDIF In rock engineering, the laboratory tests sometimes may not be able to reflect the real conditions of rocks in the field. As you know, why the laboratory tests may not be representative for rock masses in the field. Also, based on the rock coring, please explain the definitions of core recovery ratio (CR) and rock quality designation (RQD). Also, which index (CR or RQD) may reflect more representative quality of rocks from the recovered samples and why? (10 pts) 1. Create PDF O Edit PDF Comment Combine Files Organize Pages Fill &Sign; Send for Signature -Send & Track More Tools 2. Based on the landslide occurrences, list five possible triggering factors for landslides, what is the difference between the triggering factors and the conditional factors. (15 pts) Store and share files in the Document Cloud Learn More O Type here to search ?1121 AM 4/18/2018

Explanation / Answer

Core recovery ratio=(length of intact pieces of core/length of run)*100

It represents the disturbance of the soil sample.For good sampling the recovery ratio should be 96 to 98%.

Rock quality designation=(total length of cores in pieces of 10 cm and longer/length of run)*100

RQD is used for indicating the quality of rock mass..It is defined as the sum total length of cores of the length 10 cm and longer recovered from the drilling ,expressed as a percentage of the total length of the hole drilled.

RQD indicates the quality of the rock.it measures the degree of fracturing and amount of weathering in the rock mass.100-90 =excellent rock

90-75=good rock

75-50=fair rock

50-25=poor rock

<25= very poor rock

RQD is more representative as the fractures and fissures in the rock strata can be determined.

Triggering factors for landslide.

1)Rainfall

2) Vibrations in form of earthquake

3)Risk of ground water due to capillarity

4)slope angle

5)Soil erosion and vegetation

Triggering factor are sudden factor which leads to landslide,where as conditional factors are long term factors which changes over a period of time.

Conditional factor may be termed as change in the soil properties over a period of time and triggering factor can be exampled as earthquake vibrations which causes the loss in bond between the particles and causing landslide.

Related Questions

Navigate

• Browse (All)
• Browse E
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.