论文部分内容阅读
本文從力學觀點對庫隆理論提出下列問題:(1)在解算力學問題時,每個力有三個因素都該同時考慮,但庫隆對土楔滑動面上土反力的施力點竟置之不理,因而才能對擋土墙上土壓力的傾斜角作一硬性假定,使它等於墙和土間的摩阻角,然而施力點是不能不管的,因而土壓力的傾斜角是不能離開平衡條件而被隨意指定的。(2)如果考慮了土反力的施力點,則土楔祇能在滑動面上,或在墙面上,有滑動的趨勢,而不能同時在兩個面上都有滑動的趨勢,因而庫隆的基本概念“滑動土楔”就站不住了。(3)問題關鍵在滑動面的形狀;如要使土楔在滑動面和墙面上同時有滑動趨勢,則滑動面必須是曲形面,然而庫隆採用了平直形的滑動面。(4)庫隆的土楔滑動面是從墙上最大的土壓力求出的(指主動壓力),這裏所謂“最大”是指適應各個滑動面的各個土壓力而言,但對適應墙在側傾時土壓力應有的變化來說,這個最大土壓力却正是墙上極限壓力的最小值。一般工程書籍,以為這土壓力既名為最大,就拿它來用作設計擋土墙的荷載,荷載如何能用最小的極限值呢?本文對朗金理論中的下列問題作了一些解釋:(1)朗金理論在擋土墙的位移問題上所受的限制,是和庫隆理論一樣的,竇薩基教授曾就此問題認為朗金理論是幻想,似乎是無根據的。(2)有些工程書中認為朗金理論是專為垂直的墙?
From the viewpoint of mechanics, this paper puts forward the following questions for the theory of Coulomb: (1) When solving the mechanical problem, there are three factors for each force that should be considered at the same time, but Coulomb exerts a force on the soil counteracting force on the sliding surface of the soil wedge. If you ignore it, you can make a hard assumption about the inclination angle of the earth pressure on the retaining wall, making it equal to the friction angle between the wall and the soil. However, the force point cannot be ignored, and the earth pressure tilt angle cannot leave the equilibrium condition. It is arbitrarily specified. (2) If the force point of the soil reaction force is taken into consideration, the soil wedge can only slide on the sliding surface, or on the wall surface, and there is a tendency to slide, and it cannot slide on both surfaces at the same time. The basic concept of Coulomb “slippery soil wedge” could not stand still. (3) The problem lies in the shape of the sliding surface; if the soil wedge is to slide at both the sliding surface and the wall surface, the sliding surface must be a curved surface. However, Coulomb uses a flat sliding surface. (4) Coulomb’s soil wedge sliding surface is obtained from the maximum earth pressure on the wall (referred to as the active pressure). The so-called “maximum” here refers to each earth pressure that adapts to each sliding surface, but the adaptation wall is In view of the expected change in the earth pressure during rolling, the maximum earth pressure is the minimum of the wall extreme pressure. The general engineering books, thinking that this earth pressure is called the largest, use it as a load for the design of the retaining wall. How can the load use the minimum limit? This article explains some of the following issues in the Longing Theory: (1) The limitation of Lange theory on the problem of the displacement of the retaining wall is the same as that of the Coulomb theory. Prof. Dosaki has thought that the theory of Longing is an illusion and seems to be unfounded. (2) In some engineering books, the theory of Longing is considered as a vertical wall?