Designers and builders must be aware that they are responsible for adapting engineering works to the poor soil conditions in Santiago, even if it means higher costs for removing poor quality soils and higher costs for piles to transfer loads to deeper substrates.
SANTO DOMINGO.- Regarding the landslides that occurred in Santiago de los Caballeros, geologist Osiris de León attributes them to the fact that engineers do not conduct investigations to determine the most feasible locations for construction, arguing that nowadays the priority is to minimize expenses when it comes to soil studies.
“The recent collapses observed in clay soils in the city of Santiago de los Caballeros, where some engineers confuse the cause (the push of the saturated clay due to torrential rains) with the effect (the collapse of the wall pushed by the saturated clay, which would not have collapsed if it hadn't rained torrentially), have triggered alarm bells of concern in a significant part of the population who are now beginning to see and understand what some engineers refuse to understand,” the geologist states in an article published today in the newspaper Hoy.
He explains that clay soils respond very differently to the rigid limestone rocks of the city of Santo Domingo, so any engineering work carried out in Santiago de los Caballeros, at ground level, underground, or especially when it is sufficiently elevated, must begin with a correct geophysical zoning, horizontal and vertical, of the entire site area, and where governments, designers and builders must be aware that they are responsible for adapting the engineering works to the very poor soil conditions of Santiago, even if it implies higher costs in the removal of poor quality soils, higher costs in piles to transfer loads to deep substrates, higher costs in internal drainage and, fundamentally, higher costs in structural reinforcement so that the structures of Santiago respond well when shaken by a strong nearby earthquake.
The expert argues that this approach is part of the first seismogeotechnical engineering course taught to humanity, and that if it were properly understood as an engineering course, then many engineers would not confuse geological problems of clays (cause) with structural problems of walls (effect).
It states that areas of rigid rock, lacking soil, are bad for agriculture, but are good for construction and urbanization due to their high load-bearing capacity and their excellent response to the presence of water and seismic loads.
“So much so that the evangelist Matthew wrote, 2,000 years ago, that the wise man builds on the rock and the foolish man builds on the sand.”.
“For geology it is more than clear that today's soils are not the result of past human actions, but rather that since the past humans have been adapting to the different types of soils they have found in each territory they have occupied, so no one should feel guilty about the physical and chemical characteristics of the different types of soils present in our habitat,” he argues.
And it continues, “although we should feel guilty for not making an effort to understand that each type of soil has different characteristics and different behaviors, especially in the presence of water, and that organic clay soils are good for agriculture but are very bad for construction and urbanization.”.
He insists in his analysis in the morning newspaper Hoy that what was easily understandable to the evangelist Matthew for primitive society 2,000 years ago is apparently difficult for some engineers today to understand. We frequently see construction on clay in Santiago, La Vega, Bonao, San Francisco de Macorís, Moca, Licey, Navarrete, Esperanza, Mao, Villa Vásquez, the lower Yuna, etc., as if it were done on rock, without anyone handing them a Bible open to chapter 7 of the Gospel of Matthew and suggesting they read verses 24 through 27.
In his analysis, he argues that from the very moment the Earth's outer crust began to cool and solidify to form an envelope of igneous rocks, a little over 4.5 billion years ago, the process of daytime molecular expansion due to the heat of solar radiation began, and the process of nighttime contraction due to local cold, processes which, combined over thousands of years, weathered and degraded the constituent molecules of the silicatic minerals that formed those primary igneous rocks. From there, as a degradation of the primary rocks, the sandy, silty, and clay soils were formed that already occupied large territorial extensions of our planet when the first human beings began to populate some extensions of the African continent.
De León states that a structural problem in a wall can occur under any circumstances, but a geological problem with clays always occurs under conditions of heavy rainfall that saturates the soil, increases its weight, reduces its shear strength, and pushes slopes and walls until they collapse.
“Unfortunately, today the priority is to minimize spending, especially when it comes to soil studies for engineering projects in a city where some construction engineers don't understand that clays exert pressure when saturated with water, and that for this reason walls built in Santiago just 30 years ago are already collapsing due to a rainfall event that saturated the clays, while the Cathedral of Santa María la Menor, built on limestone with sound engineering principles, remains standing 500 years after its construction, after 10 major earthquakes that have shaken our island, and after powerful hurricanes that have dumped large volumes of rain on its foundations and walls, without causing any failure, while similar colonial walls, built on the clays of Santiago and La Vega, collapsed in the 1562 earthquake.”.
