What if the retaining wall is poorly designed?

When designing a retaining wall, the basic information you should have mainly includes the following aspects.

1. Overall design data of the building

Retaining wall is an integral part of the whole hub or single building. In order to meet the requirements of connection, soil retaining, water flow, seepage prevention and drainage between hub or single building and subgrade, the following information related to overall design is needed:

(1) construction engineering grade and design standard;

(2) The general layout of the building, and determine the plane and elevation layout requirements and basic dimensions of the retaining wall according to the general layout requirements;

(3) Various water levels before and after the wall during design, completion, normal operation and construction;

(4) According to the overall seepage control and drainage requirements, determine the lateral seepage control and drainage requirements of the retaining wall.

2. Topographic and geological plan of the city wall site

In general, the retaining wall layout is simple and there are no other special requirements, so it is not necessary to carry out large-scale (1: 500) engineering geological plan survey on the work site. The following should be 1: 500.

1: 200 engineering geological plan:

(1) It is necessary to study the plane position of retaining wall on paper;

(2) It is necessary to select topographic and geological sections in different directions, and it is difficult to select the correct location in field survey;

(3) Retaining wall design involves areas that need to be reflected in the plan, such as changing rivers, ditches, roads, buildings, etc.

3. Geological profile of wall site

In areas where the terrain or foundation soil fluctuates greatly, there should be a geological profile of the wall site. Generally speaking, the scale is consistent horizontally and vertically. When the retaining wall is very long, a smaller scale can be used, such as horizontal1:100-1:500 and vertical1:100-1:200.

4. Geological profile

Generally, the ratio of 1: 200 is adopted. The following questions should be considered when surveying and mapping:

(1) The section spacing depends on the terrain and geological changes, and the design and construction requirements shall prevail. In complex cases, the section spacing is 5-LOM, and it can be 10-25M when the foundation elevation changes little. Both ends of the wall should be properly encrypted to determine the starting and ending positions of the retaining wall.

(2) The width and accuracy of cross section should not only meet the requirements of subgrade design, but also consider the need of calculating earth pressure. Therefore, the representative section should be wider than the general section.

5. Main physical and mechanical indexes of retaining wall design

Generally, it can be determined according to the situation of foundation and fill, through investigation and test, referring to the existing engineering practice experience, or choose the recommended value of the specification; Special materials, such as clay filler or backfill for tall retaining walls, should be obtained through tests as far as possible; The pullout resistance of anchor rod, anchor plate and pull rod should be obtained through pullout test.

6. Hydrological data

Include surface water and groundwater. We should know the nature and flow direction of groundwater, so as to analyze the physical and mechanical properties of the selected soil, analyze the influence of static water and dynamic water pressure, and take necessary drainage measures.

The following information shall be collected for the underwater retaining wall:

(1) The particle size of riverbed soil, the velocity and direction of water flow, the change and undercutting of rivers, and the buried depth of retaining wall foundation are determined according to these data;

(2) Various water levels (including measured water level, dry water level and design water level) and flood peak duration in flood season, and analyze the influence of these factors on the design and construction of retaining wall.

7. Other information

(1) In frozen areas, there should be the freezing depth and frost heaving index of foundation and fill, such as frost heaving amount and frost heaving force;

(2) When there is no protective masonry in front of the wall and there is scouring water flow, there should be information on the scouring resistance of the foundation soil, so as to calculate the scouring depth and determine the buried depth of the wall foundation;

(3) Information on the influence of meteorology, earthquake and water quality on masonry.