• Title/Summary/Keyword: Volcanic clastic zones

Search Result 2, Processing Time 0.019 seconds

A Applicability Study on Single Grouted Column Method (C-RJP Grouting) for Buoyancy-Resistant Permanent Anchor in Highly Permeable Volcanic Clastic Zones (투수성이 높은 화산쇄설층에서 부력앵커 시공을 위한 단일공 차수공법 (C-RJP Grouting)의 적용성에 관한 연구)

  • Jung, Yonggun;Chae, Youngsu;Park, Byunghee;Kim, Jeongryeol
    • Journal of the Korean GEO-environmental Society
    • /
    • v.16 no.8
    • /
    • pp.5-12
    • /
    • 2015
  • In this study, buoyancy-resistance permanent anchor was considered to prevent uplift pressure of a building structure. However, this test was failed to put anchor body in the boring hole because of the rapid outflow of ground water and coefficient of permeability. In addition, the hole where the anchor body was forcefully inserted constantly flew the sea water and cement. And it was found that anchor was not settled in the ground. In order to solve this problem, jet grouting method was applied to block the ground water and the single grouted column method was chosen to install the buoyancy-resistance permanent anchor. In this paper, the single grouted column method was applied with the general jet grouting methods and grout material was fixed by 3-field tests. These tests confirmed the effect of permeability and ground improvement with field permeability test by core sampling, Standard Penetration Test (SPT) and unconfined compression test. Confirming the stability of the buoyancy-resistance permanent anchor with installation and tension test, application of the single grouted column method in the volcanic clastic zones was verified.

Analysis of Blasting Vibration at the Irregular Layered Structure Ground (불규칙한 층상구조 지반에서의 발파진동 분석)

  • Kim, Seung Hyun;Lee, Dong Wook
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.36 no.5
    • /
    • pp.891-901
    • /
    • 2016
  • By comparing test blasting data experimented in three layered-structure polymorphic grounds to a geological profile, influence of blast vibration with respect to uncontrollable ground characteristics was analyzed. Inefficient blast have been performed without sufficient verifications or confirmations because insufficiencies with regard to experiments and data of blasting engineering on the layered structures to be irregularly repeated clinker layer consisted of volcanic clastic zones. It is difficult to quantify N values of clinkers within test blasting region because they have diverse ranges, or coverages. An absolute value of attenuation coefficient N in a field, estimated by blasting vibration predictive equation (SRSD), are lesser than criteria of a design instruction, meaning that vibrations caused by blast can spread far away, and the vibrational characteristics of blasting test No.1, indicating relatively small values, inferred by the geological profile, pressures of gas by the explosion may be lost into a widely distributed clinker layers by penetrating holes resulted from blast into vicinity of clinker layers located in bottom of soft rock layers at the moment of blast. As a result, amounts of spalling rocks are decreased by almost half. Also, ranges of primary frequencies in the fields are identified as similar to those of natural frequency of typical structures.