@phdthesis{oai:muroran-it.repo.nii.ac.jp:00010459,
 author = {PHAM, Quang Vuong and フェム, クァン ヴォン},
 month = {2021-06-23, 2021-06-23},
 note = {application/pdf, 建設工事現場の掘削土は発展途上国の大都市において深刻な問題である。建設工事による掘削土を再利用する有効な手法である流動化処理土は，日本において一般的になっている。流動化処理土は，水，土，及びセメント系固化材を混合したスラリータイプのセメント改良土の一種である。流動化処理土は，締固めることなく安定な地盤を造成するばかりでなく，遠い距離からポンプ圧送によって空隙を容易に充填することができる。本研究では，流動化処理土の変形特性と新たな利点が建設工事の実務での適用を促進することを検討するために，実験的及び解析的な研究が実施された。本研究は以下のように要約される。(1) 原位置で作製された流動化処理土の強度・変形特性に及ぼす養生日数，養生温度，養生環境など種々の要因の影響が検討された。大学構内に2つのピットが掘削され，それぞれ，0及び10 kg/cm3の繊維材を混合した流動化処理土で埋戻した。養生日数28日及び56日後に，模型地盤から採取された流動化処理土をトリマーで成形して供試体を作製した。一連の圧密非排水三軸圧縮試験（CUB）が，原位置で作製された供試体に対して，軸ひずみ速度0.054 %/min，有効拘束圧98 kPaの条件で実施された。また，小型FWD試験による繊維材混合流動化処理土の埋戻し地盤の剛性評価に関する適用性が検討された。試験結果より，養生温度は流動化処理土の最大軸差応力qmaxに影響を及ぼし得ること，繊維材混合流動化処理土では，養生日数が増加するとqmax は養生温度の影響を受けにくくなることが明らかにされた。また，初期変形係数E0に及ぼす養生温度の影響は，養生日数の影響に比べて小さい。繊維材混合流動化処理土の養生初期においては，流動化処理土に繊維材を混合することがせん断中の損傷程度を減少させると考えられる。小型FWDによるK値は，繊維材混合流動化処理土による埋戻し地盤の剛性を適切に評価し得ることが明らかにされた。(2) 地震動を受ける建物と地盤に及ぼす埋戻し材の影響が有限要素法を用いて解析された。建物と地盤の3次元モデルは，ABAQUSソフトによりシミュレーションされた。本シミュレーションでは，各方向に4 mの3スパンからなる16本の柱で，高さ30 m，幅12 mのRC10階建て及び地下1階の構造物が選択された。八戸（日本）における1968年十勝沖地震を，時刻歴解析を行うために有限要素数値解析モデルに適用した。裏込め土（砂質土），流動化処理土，繊維材混合流動化処理土の3種類を用いた3ケースで解析した。解析結果より，埋戻し材に流動化処理土を用いると，地震時における建物の側方変位と層間変位がわずかに減少することが明らかとなった。一方，埋戻し材としての流動化処理土の適用は，建物および近隣域の周辺地盤の加速度と速度を顕著に減少させる。したがって，流動化処理土は建物と周辺地盤に及ぼす地震動を減少させるための有効な潜在能力を持つと考えられ，この特性は流動化処理土の新たな利点である。以上より，地震動を受ける地盤に対する埋戻し材としての流動化処理土の適用に関する新たな知見が示された。, Excavated soil from the construction site is a serious problem in the big city in developing countries. Liquefied Stabilized Soil (LSS), which is an effective method of reusing excavated soil with construction works has become popular in Japan. The LSS is a kind of cement-treated soil of slurry type prepared by mixing soil, water and cement solidification. The LSS are not only created stabilized ground without compaction but also easy to be able to fill empty space by pumping a long distance. In this study, the deformation characteristic and new advantage of LSS were investigated to promote the application of LSS in construction practice. Research works, including experiments and analyses, have been conducted. This study is summarized as follows: (1) The effects of various factors, which are curing days, paper content, curing temperature and curing circumstance, etc., on strength and deformation property of LSS prepared at field were investigated. Two pits were excavated on the campus and then were filled with LSS mixed with fiber material amount 0 and 10 kg/m3, respectively. After a curing time of 28 and 56 days, the specimens were prepared by trimming LSS retrieved from the model ground. A series of Consolidated-Undrained triaxial compression tests with pore water measurement (CUB test) was carried out on the specimens cured in the field ground under the conditions at an axial strain rate of 0.054 %/min and the effective confining pressure of 98 kPa. And also, the applicability of an evaluation of stiffness by the Portable FWD test (Falling Weight Deflectometer test) at a backfilling ground by LSS mixed with fiber material was investigated. Based on the test results, it was found that the curing temperature could affect the maximum deviator stress qmax of LSS. As for LSS with fiber material, there is independent of the qmax on the curing temperature when curing days increase. And the effect of curing temperature on Initial Young’s modulus E0 is smaller than that of curing days. It was considered that during the first period of the curing process of LSS mixed fiber material, the addition of the fiber material into LSS is reduced the damage degree during shear. It was found that the K-value by portable FWD can be adequately evaluated the stiffness of backfilling ground by LSS with fibered material. (2) The effect of backfilling material on the building and ground subjected to seismic motion is analyzed by using the finite element method (FEM). A three-dimensional model of the building and ground was simulated in ABAQUS software. A reinforced concrete ten-floor building frame, 30 m high and 12 m wide with 16 columns consisting of three spans of 4 m in each direction, and one basement was selected in this simulation. The 1968 Tokachi-Oki earthquake in Hachinohe (Japan) was selected and utilized on the finite element numerical model to conduct a time-history analysis. Three case studies with three types of backfilling material: backfilling soil (sandy soil), LSS, and LSS with fiber were analyzed. Base on the analysis results, it was found that using LSS as a backfilling material slightly reduce the lateral displacement and inter-story drift of building under the seismic condition. On the other hand, the application of LSS as a backfill material significantly reduce the acceleration and velocity of the ground around the building and adjacent areas. Therefore, it is considered that the LSS has an effective potential to reduce the seismic motion on the buildings and the surrounding ground. This property is a new advantage of LSS.},
 school = {室蘭工業大学, Muroran Institute of Technology},
 title = {Application of Liquefied Stabilized Soil as Backfilling Material to Ground Subjected to Seismic Motion},
 year = {}
}