土壁構造実験.JPG
Horizontal force test

伝統土壁構法の研究

Traditional Japanese Mud Wall

2007~

材料の性質/​力学的性質の解明

Properties of Materials / Mechanical Properties

小舞土壁の力学特性に及ぼす下地形態、練り土の性質および塗付け方法の影響に関する研究

The Influence of the Configurations of Lath, the Properties of Wall Clay and the Plastering Methods on Mechanical Behavior of Clay Wall on Bamboo Lathing

近年,環境負荷の少ない小舞土壁構法が見直されている.ところが,品質・性能を重んじる今日においてこの構法を採用するには,第一に構造耐力の確保が必要である.構造耐力に関しては,実大試験体を用いた加力実験が多数の研究期間で行われており,近年ではこれらの結果の蓄積によって壁倍率の告示が改正されるなど,建築法規上での評価は徐々に向上している.しかし,この壁倍率による評価では,初期剛性が重視され,小舞土壁ではの有する優れた靭性が適正に評価されているとは言い難い状況にある.また,小舞土壁では,使用材料の殆どが各地で入手可能な天然素材であることに加え,特に左官技術については試行錯誤の伝承によって修練したものであるため,練り土の性質や塗付け工程などに地域差があり,その結果として施工後の品質・性能にも優劣の差が大きい.

​本研究は,小舞土壁の力学特性に及ぼす下地形態,練り土の性質および塗付け工程の影響を明らかにし,初期剛性のみならず,元来の優れた特徴である靭性を生かす条件を見出すことを目的とした.

研究の成果は早稲田大学 輿石直幸教授のご指導のもと博士学位論文にまとめた.

In recent years, the Clay Wall on Bamboo Lathing, which has less environmental impact, has been reviewed. However, in order to adopt this construction method in today's world where quality and performance are important, it is necessary to secure the structural capacity first. In recent years, based on the accumulation of these results, the wall ratio has been revised, and the evaluation in the building regulations has gradually improved. In recent years, the evaluation of the wall ratio has been gradually improved by the accumulation of these results. However, the evaluation by the wall ratio emphasizes the initial stiffness, and it is difficult to say that the excellent toughness of the Clay Wall on Bamboo Lathing is properly evaluated. In addition to the fact that most of the materials used in the construction of Clay Wall on Bamboo Lathing are natural materials available in various regions, the plastering technique in particular has been developed through trial and error.

The purpose of this study was to clarify the effects of the base form, the nature of the kneaded soil and the coating process on the mechanical properties of Clay Wall on Bamboo Lathing, and to find the conditions to utilize not only the initial stiffness but also the toughness, which is an excellent characteristic of the original.

長野県神城断層地震における民家の土壁の破損状況とその仕様の関係

THE RELATION BETWEEN DAMAGE STATES AND SPECIFICATION OF THE JAPANESE TRADITIONAL CLAY WALL DAMAGED BY KAMISHIRO FAULT EARTHQUAKE IN NAGANO PREFECTURE

2014 年 11 月 22 日に長野県北部を震源とするマグニチュード 6.7 の長野県神城断層地震が発生した。土壁の地震被害については、ひび割れやはく落の状況の記録にとどまることが多いが、併せて 下地の破損状況や下地・土壁層の仕様を調査することで、抵抗の状況 や破損の原因を分析可能と考えられる。そこで本研究では、長野県神城断層地震における民家の土壁の破損 状況とその仕様を調査し、抵抗要素の抵抗状況 を把握するとともに、破損状況に対する土壁仕様の影響を分析した。

Japanese traditional clay wall on bamboo lathing was investigated that damaged by Kamishiro fault earthquake in Nagano prefecture on November 22, 2014. We confirmed damage states and revealed materials, plastering methods and the lath configurations of the clay wall. As a result, the resistance mechanism against the earthquake was confirmed. Causes of the delamination of the front and back sides of the clay wall layers were revealed; without gaps between bamboo lath and timber framework, falling batten or bamboo lath from timber framework, and with weakness of the sticking force of clay wall layers.